阅读说明：本技术 一种具有复合结构的快恢复二极管及其制造方法 (A kind of fast recovery diode and its manufacturing method with composite construction ) 是由 关世瑛 王金秋 于 2019-09-28 设计创作，主要内容包括：本发明公开了一种具有复合结构的快恢复二极管器件,器件具有通过深沟槽绝缘层隔离的两种类型漂移区的PN结并联结构,第一PN结以N型半导体为漂移区,第二PN结以P型半导体为漂移区,第二PN结的阴极区的掺杂浓度高,与第一PN结的第一副漂移区相接,且存在高浓度的原位多子载流子,将与正向工作时在第一PN结的漂移区内积累的空穴载流子发生复合,并能增加电子空穴对的复合率,因此同等条件下,可进一步加快反向恢复过程,获得更低的反向恢复时间Trr值,使本器件具有更优的优值。另外本发明,提出的制造流程,与传统的快恢复二极管芯片制造设备兼容,可以容易的实现本发明的一种具有复合结构的快恢复二极管器件。(The invention discloses a kind of fast recovery diode device with composite construction, device has the PN junction parallel-connection structure for the two types drift region being isolated by deep trench insulated layer, first PN junction is using N-type semiconductor as drift region, second PN junction is using P-type semiconductor as drift region, the doping concentration in the cathodic region of the second PN junction is high, connect with the first secondary drift region of the first PN junction, and there are the how sub- carriers in situ of high concentration, the holoe carrier accumulated in the drift region of the first PN junction when working with forward direction is occurred compound, and it can increase the recombination rate of electron hole pair, therefore under equal conditions, reversely restoring process can be further speeded up, obtain lower reverse recovery time Trr value, make this device that there is the more preferably figure of merit.In addition of the invention, the manufacturing process of proposition is compatible with traditional fast recovery diode chip manufacturing equipment, and a kind of fast recovery diode device with composite construction of the invention can be easily realized.)

1. a kind of fast recovery diode device with composite construction, it is characterised in that structure includes: on cathode metal layer 19 There is the first semiconductor conducting layer 1, there is the second semiconductor conducting layer 2 on the first semiconductor conducting layer 1, in the second semiconductor conduction There is third semiconductor conducting layer 3 on layer 2；By mask etching, form groove, groove through third semiconductor conducting layer 3 until In second semiconductor conducting layer 2；Region is device source region 20 between in the devices, and region portions form wide groove, wide trenched side-wall There is the covering of the first insulating layer 12, the 4th semiconductor conducting layer 11 is arranged at bottom in wide groove, has on the 4th semiconductor conducting layer 11 5th semiconductor conducting layer 13；There is the 6th semiconductor conducting layer 16 on third semiconductor conducting layer 3 in source region, in source region There is the 7th semiconductor conducting layer 17 on five semiconductor conducting layers 13；There is narrow ditch in device terminal area 30 except the source region of device Slot is filled in narrow groove by the first insulating layer 12, has third insulating layer 15 on the first insulating layer 12 of narrow groove；In device There is second insulating layer 14 on the third semiconductor conducting layer of termination environment, there is third insulating layer 15 in second insulating layer 14；Device There are anode metal layer 18, the 6th semiconductor conducting layer 16 of source region and 17 upper surface of the 7th semiconductor conducting layer and anode in upper surface Metal layer Ohm connection；There is cathode metal layer 19 in the lower surface of device, and the first semiconductor conducting layer 1 connects with cathode metal layer ohm It connects.

2. a kind of fast recovery diode device with composite construction as described in claim 1, it is characterised in that: the first half lead Body conductive layer 1 is the N-type silicon materials of heavy doping, the substrate layer as device；Third semiconductor conducting layer 3 is low-doped N-type Silicon materials, as the first main drift region of device, i.e. reverse withstand voltage area；Second semiconductor conducting layer 2 is N-type silicon materials, doping First secondary drift of the concentration between the first semiconductor conducting layer and the doping concentration of third semiconductor conducting layer, as device Area, i.e. reverse withstand voltage buffer layer area, and undertake a part of reverse withstand voltage；4th semiconductor conducting layer 11 is N-type silicon materials, upper, Lower both ends doping concentration is low, but the doping concentration of doping concentration lowest part is higher than the doping concentration of the second semiconductor conducting layer, and Middle area doping concentration highest is higher than 2 orders of magnitude of lowest part or more；5th semiconductor conducting layer 13 is low-doped p-type Silicon materials, the second main drift region as device；6th semiconductor conducting layer 16 and the 7th semiconductor conducting layer 17 are P-type silicon material Material, is the doped region of the diffusion junction structure of high-concentration dopant, and the 6th semiconductor conducting layer 16 is formed with third semiconductor conducting layer First PN junction of device, the second PN junction of the 7th semiconductor conducting layer 17 and the 5th semiconductor conducting layer formation device, the 6th half The upper surface of conductor conductive layer and the 7th semiconductor conducting layer and anode metal layer 18 form Ohmic contact；The all of device partly lead The beavy metal impurity of low equivalent, such as platinum are doped in body conductive layer.

3. a kind of fast recovery diode device with composite construction as described in claim 1, it is characterised in that: the first insulation Layer 12, second insulating layer 14, third insulating layer 15 are thick semiconductor insulating material, wherein the first insulating layer is thermally grown oxygen SiClx and silicon oxide deposition collectively constitute, and the thickness value of the first insulating layer is far below the value of the half of the width value of wide groove, far Greater than the value of the half of the width value of narrow groove；Second insulating layer be thermally grown formation silica, 500 nanometers of thickness or more, Third insulating layer is to deposit the silica formed, 500 nanometers of thickness or more.

4. a kind of fast recovery diode device with composite construction as described in claim 1, it is characterised in that: there are two types of tools The drift region of type, forms composite construction in parallel by the first insulator separation, the 6th semiconductor conducting layer of the device with The PN junction that third semiconductor conducting layer is formed, constitutes the first PN junction of device, and third semiconductor conducting layer is the of the first PN junction One main drift region is N-type drift region；The PN junction that 5th semiconductor conducting layer and the 4th semiconductor conducting layer are formed, constitutes device The second PN junction, the 5th semiconductor conducting layer be the second PN junction the second main drift region, be P drift area, cathodic region be the 4th Semiconductor conducting layer can provide how sub- carrier on direction of an electric field, improve reversely restoring process in reversely restoring process In, when forward conduction, is accumulated in the recombination rate of few sub- carrier in buffer layer, improves recombination velocity under equal conditions, reduces device The reverse recovery time of part.

5. a kind of fast recovery diode device with composite construction as described in claim 1, it is characterised in that: terminal structure Using the terminal protection of deep trench insulated layer, area occupied is small, and can effectively reduce skin effect, reduces leakage current, again Breakdown electric field can be introduced in vivo, improve breakdown voltage, make fast recovery diode of the invention that there is the more preferably figure of merit.

6. a kind of manufacturing method of fast recovery diode device with composite construction of the invention, it is characterised in that: can be formed A kind of manufacturing process of fast recovery diode device with composite construction with composite construction, includes the following steps:

A, it is silicon substrate with the first semiconductor conducting layer of the N-type of heavy doping 1, it is low that one layer of doping concentration is first generated by epitaxy technology In the second semiconductor conducting layer 2 of the N-type of silicon substrate concentration, then the extension by reducing doping concentration, form the third half of N-type Conductor conductive layer 3 forms thick second insulating layer 14 on the surface of third semiconductor conducting layer by thermally grown mode；It passes through again First time photoetching, etching are crossed, after etching 14 silicon oxide layer of second insulating layer, is further continued for etching silicon, the depth value for etching silicon is greater than 3 thickness value of third semiconductor conducting layer is less than 2 thickness value of third semiconductor conducting layer thickness value and the second semiconductor conductive material The sum of, the lines of different in width are designed in reticle, are formed the groove of different in width, are formed narrow groove in edge termination region, in Between source region form wide groove；

B, after by second of thermally grown one layer of silica, then the silicon oxide layer of a thickness is deposited, the first insulating layer is collectively formed 12, total thickness value is greater than more than half of narrow groove width value, and is less than the value of the half of the width value of wide groove, finally It is laterally filled up in narrow groove, wide groove does not fill up, only one layer of covering, i.e. the first insulating layer fills up narrow groove, covers wide channel side The state of one layer of wall and bottom, then by anisotropic etching, the first insulating layer of channel bottom is etched away, while by surface The first insulating layer etch away；Again by epitaxial growth, time quarter, repeats growing epitaxial silicon, returns quarter process, it is raw in wide groove Long doping concentration is higher than the N-type silicon of the second outer layer doping concentration, and outer delay is adjusted the 4th by adjusting the concentration of doped source The concentration distribution of semiconductor conducting layer makes in-between regional concentration be higher than the concentration of upper/lower terminal, ultimately forms the 4th semiconductor Conductive layer 11, the thickness value of the 4th semiconductor conducting layer, less than the extension thickness of trench depth value and third semiconductor conducting layer The difference of angle value；Again by changing the type of the doped source of epitaxial process, continues epitaxial growth repeatedly, returns quarter process, Low-doped P-type silicon is grown in wide groove, forms the 5th semiconductor conducting layer 13, the 5th semiconductor conducting layer thickness is until filling out Stop epitaxial growth when the surface level of full width groove and third semiconductor conducting layer, return quarter process, due to epitaxial process temperature It is higher, and the doping concentration of the 4th semiconductor conducting layer is higher than the doping concentration of the second semiconductor conducting layer, therefore the 4th half leads The impurity of doping in body conductive layer can be spread downwards, form reclinate doped interface；

C, thick silica is deposited using deposit mode, forms third insulating layer, it, will using second of photoetching, corrosion process The second insulating layer of the intermediate area surface of device, third insulating layer erode；Again by p type impurity injection, knot, one is formed The high concentration P-type silicon of depthkeeping degree finally forms the 6th semiconductor conducting layer on the third semiconductor conducting layer in source region, the The 7th semiconductor conducting layer is formed on five semiconductor conducting layers, while the impurity of the 4th semiconductor conducting layer will continue to downwards It slightly spreads again, forms curved surface distribution in channel bottom, form the 4th final semiconductor conducting layer region, then carry out drift acid, The thin oxide layer formed in source region silicon face in knot process is eroded, exposes the 6th semiconductor conducting layer, the 7th semiconductor is led The silicon face of electric layer；

D, a thin layer platinum is overleaf sputtered or be deposited, then by short annealing, forms heavy metal platinum dopant, wet etching is gone Fall the platinum of excess surface；One layer of metal layer is formed in anode surface by the way of sputtering or evaporation again, using third Secondary photoetching, metal layer corrosion, form anode metal layer 18, by alloying, anode metal and the 6th semiconductor conducting layer, the 7th The surface of semiconductor conducting layer forms Ohmic contact；The lining of bottom is thinned using physical grinding mode, then carries out back-side gold Belong to layer sputtering or vapor deposition, forms back side cathode metal layer 19, ultimately form entire device architecture.

7. a kind of manufacturing method of the fast recovery diode device with composite construction as claimed in claim 6, feature exist In: by insulator separation, then using epitaxial growth, time quarter, then epitaxial growth, the repetition epitaxial growth for returning quarter, fill groove； In extension four semiconductor conducting layer of growth regulation, using the concentration of side doped source, the doping concentration for forming intermediate region is higher than The doping concentration of upper/lower terminal, the doping concentration of the 4th semiconductor conducting layer doping concentration lowest part are higher than the second semiconductor and lead The doping concentration of electric layer；Change the type of doped source, the 5th semiconductor conducting layer of the low doping concentration of growing P-type, anti-again It can provide more how sub- carriers to recovery latency direction of an electric field, what is accumulated when improving positive lacks the compound several of sub- carrier Rate, therefore under same condition, there is lower reverse recovery time；The 5th semiconductor conducting layer being additionally formed, has device There is another type of drift region, is formed with the fast recovery diode device of the composite construction of two kinds of drift regions, and whole A process flow only uses 3 photoetching, compared with the photoetching number of the fast recovery diode of traditional structure, a few polycrystalline photoetching, and drop Low photoetching cost.

Technical field

The present invention relates to a kind of fast recovery diode and its manufacturing process, relate generally to a kind of fast extensive with composite construction Multiple diode and its manufacturing method.

Background technique

The characteristic that diode has forward conduction, reversely ends is widely used as a kind of electric switch use, diode type It is various, but the functions such as rectification, afterflow, clamper are typically used as, it is applied in various circuits；Once it is referred to as " ideal electricity in early days Switch " is the presence of loss, the electrical loss of diode is also referred to as almost without electrical loss, but during actual use diode For power consumption, including on-state power consumption, OFF state power consumption, switching process power consumption, especially as the progress of technology, the electrical loss of diode is drawn Play more concerns；Industry technology personnel are continuous to optimize by continuous technological innovation according to different application needs The characteristic of diode, to realize the lowest power consumption state in diode use process, to meet the needs of different application；Its In with PFC high frequency electric source appearance, the switching power loss of diode is more obvious, therefore a kind of high frequency that is suitable for uses, and has The diode of low switching power loss comes into being, i.e. fast recovery diode.Fast recovery diode is a kind of bipolar device, is belonged to PIN diode, more common PIN diode compare, and have the characteristics that reverse recovery time is short, switching loss is low, are suitable for high frequency The workplace of switch is widely used in high frequency electric source occasion, such as: the neck such as PFC power supply, electric welding machine, inverter, frequency converter Domain.

Reverse recovery time (Trr) parameter of fast recovery diode, is the weight of the reverse recovery characteristic of fast recovery diode Want index, under equal conditions, Trr value is smaller, and Reverse recovery is fast, more suitable frequency applications, therefore pursues lower Reverse recovery Time (Trr) becomes the striving direction of industry technology personnel, various technologies is developed, to obtain the low of fast recovery diode Trr value.Currently used technology has electronic irradiation technique, heavy metal doping techniques, proton doping techniques etc., and Trr value is main Related with minority carrier life time, electron-hole recombination rate, current technology mainly passes through increase trap, increases capture face, improves multiple Probability is closed, minority carrier life time is reduced, to realize the low Trr characteristic of fast recovery diode.It is fast to restore but in the case of current technology Diode Trr cannot be reduced infinitely, low to obtain by along with the degeneration of other performances because when Trr is further decreased Trr value needs the increase of electron irradiation dosage, heavy metal doping concentration aggravate, proton doping density improves etc., will appear in this way The adjustment of minority carrier life time is excessive, thus reduces the mobility of carrier, so that forward saturation voltage drop occurs in fast recovery diode VF is increased, while the reverse breakdown characteristics of fast recovery diode can also degenerate, and soft breakdown occur, reverse leakage current Ir increases to ask Topic.Therefore every kind of technology is all to use in a certain range, carries out the tradeoff design of parameter, obtains the optimal figure of merit, is realized full It is enough to the optimized parameter of application requirement, the figure of merit of device is lower, and the power consumption under working condition is lower.Currently used technology, Such as electronic irradiation technique, when adjusting the Trr of fast recovery diode, large dosage of irradiation fast recovery diode will appear reversed leakage Electric current Ir significantly increases, especially hot operation when be particularly acute, therefore be not suitable for high temperature applicationss work application, if When hot operation, or even it will appear Trr value and become larger, and after temperature recovery, Trr value is also become larger；Heavy metal doping techniques, which use, to be mixed Miscellaneous heavy metal, platinum expansion or the mode for expanding gold, using the fast recovery diode of this technology compared with the fast recovery using electronic irradiation technique Diode under equal conditions, leaks electricity low, and forward saturation voltage drop VF is higher, but hot properties is stablized, and is its important advantage；And Platinum expansion is compared with expanding gold, under equal conditions, using the fast recovery diode of platinum expansion technology also than using two poles of fast recovery for expanding gold Pipe, reverse leakage current are low；Proton doping techniques are mainly the proton of the electrification of small atom, such as the proton of H, He, are infused using similar The technology entered is doped, and can effectively form local doping, this technology is newest local carrier lifetime control technology, Since its process specifications is higher, there is presently no widespread adoptions.The requirement that optimized parameter meets application can be obtained at present, Most to use technology be the heavy metal doping techniques of source metal of being attached most importance to platinum, and increases buffer layer in drift region, buffer layer Doping concentration between substrate doping and main drift doping concentration, also make a part of the drift region of device, make For secondary drift region, when forward direction work, hole can largely run up to main drift region and secondary drift region due to sub- injection effect less In, and in reversely restoring process, since the doping concentration in situ of buffer layer is higher, it is possible to provide more electronics, it is slow with being accumulated in Complex effect occurs for the hole for rushing layer, improves the recombination rate of electron hole, can further speed up reversely restoring process, has slow The cross-section structure of the fast recovery diode of the traditional structure of layer is rushed as shown in Figure 1, and being doped using platinum as heavy metal source, shape At capture trap, the concentration increase of platinum dopant will effectively reduce Trr, but VF can be made to increase, when doping concentration reaches certain journey When spending, Trr value will slowly decline, but VF will rise rapidly, and the figure of merit of fast recovery diode will increase, and reverse leakage current Also can be out of control, therefore in practical applications, even with the design with buffer layer structure, using the condition of platinum dopant technology Under, can all there be the range of a comparatively ideal doping, i.e. it is more than this range that Reverse recovery, which can have a most fast actual value, The fast recovery diode figure of merit of platinum dopant will be deteriorated, therefore limit the application range of fast recovery diode.It is proposed by the present invention A kind of fast recovery diode device with composite construction, using a kind of composite structured design, tool is there are two types of drift region, and first PN junction with N-type drift region, the second PN junction have P drift area, this composite construction in reversely restoring process, the second PN junction The cathodic region of high-dopant concentration, in reversed electric field, it will thus provide more electronic carriers drift about when working with forward direction in N-type Holoe carrier of the area by sub- injection effect accumulation less, out movement, and increase the recombination rate of two kinds of carriers, equal conditions Under the reversely restoring process of device that further speeds up, so that device is obtained the more preferably figure of merit, structure of the invention cross-section structure such as Fig. 2 It is shown, while present invention also proposes its manufacturing method, it can be achieved that product of the invention.

Summary of the invention

The invention proposes a kind of fast recovery diode and its manufacturing method with composite construction, it is fast by composite construction The structure of recovery diode chip designs, and device has the PN junction for the two types drift region being isolated by deep trench insulated layer simultaneously It is coupled structure, the first PN junction using the N-type semiconductor of low doping concentration as drift region, partly led with the p-type of low doping concentration by the second PN junction Body is drift region, and the drift region that the cathodic region of the high-dopant concentration of the second PN junction is located at the first PN junction connects, and there are high concentrations How sub- carrier in situ, i.e. electronic carrier, in reversed electric field, by when working with forward direction in the drift region of the first PN junction It is interior, the holoe carrier of You Shaozi injection effect accumulation, out movement, and increase the recombination rate of electron hole pair, therefore same Under the conditions of, reversely restoring process can be further speeded up, lower reverse recovery time Trr value is obtained, there is this device more excellent The figure of merit.In addition of the invention, the manufacturing process of proposition is compatible with traditional fast recovery diode chip manufacturing equipment, Ke Yirong A kind of easy realization fast recovery diode device with composite construction of the invention.

The invention proposes a kind of fast recovery diode device and its manufacturing method with composite construction.

1, a kind of fast recovery diode device with composite construction, it is characterised in that structure includes: in cathode metal layer There is the first semiconductor conducting layer 1 on 19, has the second semiconductor conducting layer 2 on the first semiconductor conducting layer 1, in the second semiconductor There is third semiconductor conducting layer 3 on conductive layer 2；By mask etching, groove is formed, groove runs through third semiconductor conducting layer 3 Until in the second semiconductor conducting layer 2；Region is device source region 20 between in the devices, and region portions form wide groove, wide groove Side wall has the covering of the first insulating layer 12, and the 4th semiconductor conducting layer 11 is arranged at bottom in wide groove, in the 4th semiconductor conducting layer 11 On have the 5th semiconductor conducting layer 13；There is the 6th semiconductor conducting layer 16 on third semiconductor conducting layer 3 in source region, in source region The 5th semiconductor conducting layer 13 on have the 7th semiconductor conducting layer 17；Device terminal area 30 except the source region of device has narrow Groove is filled in narrow groove by the first insulating layer 12, has third insulating layer 15 on the first insulating layer 12 of narrow groove；In device Termination environment third semiconductor conducting layer on have second insulating layer 14, have third insulating layer 15 in second insulating layer 14；Device Upper surface have an anode metal layer 18, the 6th semiconductor conducting layer 16 of source region and 17 upper surface of the 7th semiconductor conducting layer and sun Pole metal layer Ohm connection；There are cathode metal layer 19, the first semiconductor conducting layer 1 and cathode metal layer ohm in the lower surface of device Connection.

2, a kind of fast recovery diode device with composite construction as described above, it is characterised in that: the first semiconductor is led Electric layer 1 is the N-type silicon materials of heavy doping, the substrate layer as device；Third semiconductor conducting layer 3 is low-doped N-type silicon material Material, as the first main drift region of device, i.e. reverse withstand voltage area；Second semiconductor conducting layer 2 is N-type silicon materials, doping concentration Between the first semiconductor conducting layer and the doping concentration of third semiconductor conducting layer, as the first secondary drift region of device, That is reverse withstand voltage buffer layer area, and undertake a part of reverse withstand voltage；4th semiconductor conducting layer 11 be N-type silicon materials, upper and lower two Hold doping concentration low, but the doping concentration of doping concentration lowest part is higher than the doping concentration of the second semiconductor conducting layer, and intermediate Area's doping concentration highest is higher than 2 orders of magnitude of lowest part or more；5th semiconductor conducting layer 13 is low-doped P-type silicon material Material, the second main drift region as device；6th semiconductor conducting layer 16 and the 7th semiconductor conducting layer 17 are P-type silicon material, For the doped region of the diffusion junction structure of high-concentration dopant, the 6th semiconductor conducting layer 16 forms device with third semiconductor conducting layer The first PN junction, the 7th semiconductor conducting layer 17 and the 5th semiconductor conducting layer form the second PN junction of device, the 6th semiconductor The upper surface of conductive layer and the 7th semiconductor conducting layer and anode metal layer 18 form Ohmic contact；All semiconductors of device are led The beavy metal impurity of low equivalent, such as platinum are doped in electric layer.

3, a kind of fast recovery diode device with composite construction as described above, it is characterised in that: the first insulating layer 12, Second insulating layer 14, third insulating layer 15 are thick semiconductor insulating material, wherein the first insulating layer is thermally grown oxide silicon It is collectively constituted with silicon oxide deposition, the thickness value of the first insulating layer is far below the value of the half of the width value of wide groove, is much larger than The value of the half of the width value of narrow groove；Second insulating layer be thermally grown formation silica, 500 nanometers of thickness or more, third Insulating layer is to deposit the silica formed, 500 nanometers of thickness or more.

4, a kind of fast recovery diode device with composite construction as described above, it is characterised in that: there are two types Drift region, composite construction in parallel, the 6th semiconductor conducting layer and third of the device are formed by the first insulator separation The PN junction that semiconductor conducting layer is formed, constitutes the first PN junction of device, and third semiconductor conducting layer is the first master of the first PN junction Drift region is N-type drift region；The PN junction that 5th semiconductor conducting layer and the 4th semiconductor conducting layer are formed constitutes the of device Two PN junctions, the 5th semiconductor conducting layer are the second main drift region of the second PN junction, are P drift area, and cathodic region is led for the 4th half Body conductive layer can provide how sub- carrier on direction of an electric field, improve in reversely restoring process in reversely restoring process, It is accumulated in the recombination rate of few sub- carrier in buffer layer when forward conduction, improves recombination velocity under equal conditions, reduces device Reverse recovery time.

5, a kind of fast recovery diode device with composite construction as described above, it is characterised in that: terminal structure uses The terminal protection of deep trench insulated layer, area occupied is small, and can effectively reduce skin effect, reduces leakage current, and can incite somebody to action Breakdown electric field introduces in vivo, improves breakdown voltage, and fast recovery diode of the invention is made to have the more preferably figure of merit.

6, the manufacturing method of a kind of fast recovery diode device with composite construction of the invention, it is characterised in that: can The manufacturing process for forming a kind of fast recovery diode device with composite construction with composite construction, includes the following steps:

A, it is silicon substrate with the first semiconductor conducting layer of the N-type of heavy doping 1, it is low that one layer of doping concentration is first generated by epitaxy technology In the second semiconductor conducting layer 2 of the N-type of silicon substrate concentration, then the extension by reducing doping concentration, form the third half of N-type Conductor conductive layer 3 forms thick second insulating layer 14 on the surface of third semiconductor conducting layer by thermally grown mode；It passes through again First time photoetching, etching are crossed, after etching 14 silicon oxide layer of second insulating layer, is further continued for etching silicon, the depth value for etching silicon is greater than 3 thickness value of third semiconductor conducting layer is less than 2 thickness value of third semiconductor conducting layer thickness value and the second semiconductor conductive material The sum of, the lines of different in width are designed in reticle, are formed the groove of different in width, are formed narrow groove in edge termination region, in Between source region form wide groove；

B, after by second of thermally grown one layer of silica, then the silicon oxide layer of a thickness is deposited, the first insulating layer is collectively formed 12, total thickness value is greater than more than half of narrow groove width value, and is less than the value of the half of the width value of wide groove, finally It is laterally filled up in narrow groove, wide groove does not fill up, only one layer of covering, i.e. the first insulating layer fills up narrow groove, covers wide channel side The state of one layer of wall and bottom, then by anisotropic etching, the first insulating layer of channel bottom is etched away, while by surface The first insulating layer etch away；Again by epitaxial growth, time quarter, repeats growing epitaxial silicon, returns quarter process, it is raw in wide groove Long doping concentration is higher than the N-type silicon of the second outer layer doping concentration, and outer delay is adjusted the 4th by adjusting the concentration of doped source The concentration distribution of semiconductor conducting layer makes in-between regional concentration be higher than the concentration of upper/lower terminal, ultimately forms the 4th semiconductor Conductive layer 11, the thickness value of the 4th semiconductor conducting layer, less than the extension thickness of trench depth value and third semiconductor conducting layer The difference of angle value；Again by changing the type of the doped source of epitaxial process, continues epitaxial growth repeatedly, returns quarter process, Low-doped P-type silicon is grown in wide groove, forms the 5th semiconductor conducting layer 13, the 5th semiconductor conducting layer thickness is until filling out Stop epitaxial growth when the surface level of full width groove and third semiconductor conducting layer, return quarter process, due to epitaxial process temperature It is higher, and the doping concentration of the 4th semiconductor conducting layer is higher than the doping concentration of the second semiconductor conducting layer, therefore the 4th half leads The impurity of doping in body conductive layer can be spread downwards, form reclinate doped interface；

C, thick silica is deposited using deposit mode, forms third insulating layer, it, will using second of photoetching, corrosion process The second insulating layer of the intermediate area surface of device, third insulating layer erode；Again by p type impurity injection, knot, one is formed The high concentration P-type silicon of depthkeeping degree finally forms the 6th semiconductor conducting layer on the third semiconductor conducting layer in source region, the The 7th semiconductor conducting layer is formed on five semiconductor conducting layers, while the impurity of the 4th semiconductor conducting layer will continue to downwards It slightly spreads again, forms curved surface distribution in channel bottom, form the 4th final semiconductor conducting layer region, then carry out drift acid, The thin oxide layer formed in source region silicon face in knot process is eroded, exposes the 6th semiconductor conducting layer, the 7th semiconductor is led The silicon face of electric layer；

D, a thin layer platinum is overleaf sputtered or be deposited, then by short annealing, forms heavy metal platinum dopant, wet etching is gone Fall the platinum of excess surface；One layer of metal layer is formed in anode surface by the way of sputtering or evaporation again, using third Secondary photoetching, metal layer corrosion, form anode metal layer 18, by alloying, anode metal and the 6th semiconductor conducting layer, the 7th The surface of semiconductor conducting layer forms Ohmic contact；The lining of bottom is thinned using physical grinding mode, then carries out back-side gold Belong to layer sputtering or vapor deposition, forms back side cathode metal layer 19, ultimately form entire device architecture.

7, a kind of manufacturing method of the fast recovery diode device with composite construction as described above, it is characterised in that: By insulator separation, then using epitaxial growth, time quarter, then epitaxial growth, the repetition epitaxial growth for returning quarter, fill groove；In When four semiconductor conducting layer of epitaxial growth, using the concentration of side doped source, formed intermediate region doping concentration be higher than it is upper, The doping concentration of the doping concentration at lower both ends, the 4th semiconductor conducting layer doping concentration lowest part is higher than the second semiconductor conducting layer Doping concentration；Change the type of doped source, the 5th semiconductor conducting layer of the low doping concentration of growing P-type, reversed extensive again Multiple time delay direction of an electric field can provide more how sub- carriers, the recombination probability of the few sub- carrier accumulated when improving positive, because Under this same condition, there is lower reverse recovery time；The 5th semiconductor conducting layer being additionally formed, is provided with device separately A type of drift region is formed with the fast recovery diode device of the composite construction of two kinds of drift regions, and entire technique Process only uses 3 photoetching, and compared with the photoetching number of the fast recovery diode of traditional structure, a few polycrystalline photoetching reduces photoetching Cost.

A kind of fast recovery diode with composite construction of the invention, has two kinds of drift region, and one kind is that N floats Shifting area, one kind are P drift area, both drift regions form isolation parallel-connection structure, and P drift area by insulator separation Cathode be that the N-type region of high concentration can provide how sub- carrier along direction of an electric field when Reverse recovery, accelerate positive What is accumulated when work lacks the compound of sub- carrier, to promote Reverse recovery efficiency, reduces reverse recovery time, realizes to reduce and open Close the effect of power consumption.

Detailed description of the invention

Fig. 1 is the fast recovery diode diagrammatic cross-section of traditional structure.

Fig. 2 is a kind of diagrammatic cross-section of fast recovery diode device with composite construction of the invention.

Fig. 3-Fig. 9 is the pilot process section to form a kind of fast recovery diode device with composite construction of the invention Schematic diagram.

Specific embodiment

Fig. 1 shows the diagrammatic cross-section of the fast recovery diode of traditional structure in the market, device junction shown in figure Structure, on the N-type semiconductor material silicon materials N+ layer of heavy doping, to there is N layers of extension of one layer of doping, N layers have N- layers of extension above, N layers of doping concentration are between N+ layers of doping concentration and N- layers between doping concentration；There is insulating medium layer 5 on N- layers, by light It carves, the injection of burn into p type impurity, knot, forms p-type doped diffusion region 4, the p type diffusion region of central area forms source region, edge The p type diffusion region of termination environment forms potential dividing ring, has polycrystalline field plate 6, side on the dielectric layer of the outer at the edge and potential dividing ring of source region Insulating medium layer 7 is deposited on the polycrystalline field plate of edge area termination environment forms insulation protection；The P-doped zone domain of the source region of central area With metal ohmic contact, anode metal 8 is formed；The bottom N+ and metal ohmic contact form cathodic metal 9；The semiconductor of device A certain amount of heavy metal is adulterated in area, is formed and captures trap, reduction carrier lifetime, the reverse recovery time of adjusting means, finally Form fast recovery diode device.Structure illustrates the reversely restoring process of device as shown in connection with fig. 1, when device anode 8 applies just When voltage, after reaching P-doped zone 4 and the Built-in potential of the PN junction of N- layers of formation, PN junction forward conduction, the mostly son of p type island region Hole will pass through PN junction under electric field action, be injected into N- layers, N layers, and form accumulation and hole and form few son in N- layers, N layers Injection accumulation, reduces the resistivity of N- layers with N layers, forms conductivity modulation effect, the hole concentration tired out at this time in N- layers, N lamination Much higher than N- layers, N layers of original doping concentration；When process of the device from forward conduction to shutdown, i.e., after forward conduction again When anode applies negative voltage, theoretically PN junction diode is reversely ended, but in practice, and PN junction diode is in forward conduction shape When state is converted to reverse blocking state, the hole for the high concentration tired out when due to forward conduction in N- layers, N lamination will not disappear at once It loses, and is to fade away by a reversely restoring process, the hole of these accumulation will adulterate the prisoner to be formed by heavy metal Obtain the reversed extraction that trap, electron-hole pair be compound and backward voltage effect is lower, formation accelerator, until reversely ending Area finally establishes completion, just reaches reverse blocking state, and during this Reverse recovery, since device is in high anti- It is existed simultaneously to pressure and big electric current, this process will generate biggish power loss, therefore industry technology personnel use various skills Art improves reversely restoring process, and to reduce the power loss of reversely restoring process generation, currently used technology has a huge sum of money Belong to doping techniques, increase buffer layer etc., wherein heavy metal adulterates, and trap defect can be formed in semiconductor, improves carrier prisoner Efficiency is obtained, carrier lifetime is reduced, realizes quick restitution, heavy metal doping concentration is higher, and capture efficiency is higher, current-carrying The sub- service life is shorter, and Reverse recovery is faster, but will lead to forward voltage drop raising, or even the phenomenon that reversed soft breakdown occur, therefore Heavy metal doping concentration will control in a certain range；In consideration of it, there is increase buffer layer technique, by improving electron hole Combined efficiency, to accelerate Reverse recovery, N layer as shown in Figure 1 has than N- layers doping concentration high, improves drift region and carries in situ Sub- concentration is flowed, i.e., electron concentration in situ, in Reverse recovery, it is possible to provide the sky accumulated when going out electronics more more than N- layers and positively biased Cave, formation electron hole pair is compound, accelerates Reverse recovery, N layers of concentration are higher, thicker, the effect of the electronics and hole-recombination that provide Rate is faster, and reverse recovery time is shorter, but it is N layers thicker, concentration is higher, will lead to conductance modulation efficiency reduction, will lead to forward direction Pressure drop increases, and also will appear the phenomenon that breakdown reverse voltage reduces.The fast recovery diode of a new generation mostly uses greatly these at present Technology is used in combination, and has reached optimal Reverse recovery state, it can be achieved that lower reverse recovery time, can accomplish 25 at present Nanosecond hereinafter, while still employing new technology, also brings along other undesirable as a result, such as forward voltage drop raising is asked Topic, therefore in the state of the art, the figure of merit of a limit is had reached as a result, can only accomplish one kind according to the demand of application The compromise of parameter, to realize the more excellent performance in application.

Fig. 2 shows a kind of diagrammatic cross-sections of fast recovery diode device with composite construction of the invention, in yin There is the first semiconductor conducting layer 1 on pole metal layer 19, there is the second semiconductor conducting layer 2 on the first semiconductor conducting layer 1, There is third semiconductor conducting layer 3 on two semiconductor conducting layers 2；By mask etching, groove is formed, groove runs through third semiconductor Conductive layer 3 is until in the second semiconductor conducting layer 2；Region is device source region 20 between in the devices, and region portions form wide groove, Wide trenched side-wall has the covering of the first insulating layer 12, and the 4th semiconductor conducting layer 11 is arranged at bottom in wide groove, leads in the 4th semiconductor There is the 5th semiconductor conducting layer 13 in electric layer 11；There is the 6th semiconductor conducting layer 16 on third semiconductor conducting layer 3 in source region, There is the 7th semiconductor conducting layer 17 on the 5th semiconductor conducting layer 13 in source region；Device terminal area except the source region of device 30 have narrow groove, are filled in narrow groove by the first insulating layer 12, have third insulating layer 15 on the first insulating layer 12 of narrow groove； There is second insulating layer 14 on the third semiconductor conducting layer of the termination environment of device, there is third insulating layer in second insulating layer 14 15；There is an anode metal layer 18 in the upper surface of device, on the 6th semiconductor conducting layer 16 of source region and the 7th semiconductor conducting layer 17 Surface and anode metal layer Ohm connection；There are cathode metal layer 19, the first semiconductor conducting layer 1 and cathode gold in the lower surface of device Belong to layer Ohm connection.First semiconductor conducting layer 1 of device is the N-type silicon materials of heavy doping, the substrate layer as device；Third Semiconductor conducting layer 3 is low-doped N-type silicon materials, as the first main drift region of device, i.e. reverse withstand voltage area；The second half lead Body conductive layer 2 is N-type silicon materials, doping concentration of the doping concentration between the first semiconductor conducting layer and third semiconductor conducting layer Between, as the first secondary drift region of device, i.e. reverse withstand voltage buffer layer area, and undertake a part of reverse withstand voltage；4th half leads Body conductive layer 11 is N-type silicon materials, and upper/lower terminal doping concentration is low, but the doping concentration of doping concentration lowest part is higher than second The doping concentration of semiconductor conducting layer, and middle area doping concentration highest are higher than 2 orders of magnitude of lowest part or more；5th half Conductor conductive layer 13 is low-doped P-type silicon material, the second main drift region as device；6th semiconductor conducting layer 16 and Seven semiconductor conducting layers 17 are P-type silicon material, are the doped region of the diffusion junction structure of high-concentration dopant, the 6th semiconductor conducting layer 16 form the first PN junction of device, the 7th semiconductor conducting layer 17 and the 5th semiconductor conducting layer shape with third semiconductor conducting layer At the second PN junction of device, the upper surface of the 6th semiconductor conducting layer and the 7th semiconductor conducting layer and the formation of anode metal layer 18 Ohmic contact；The beavy metal impurity of low equivalent, such as platinum are doped in all semiconductor conducting layers of device.The first of device Insulating layer 12, second insulating layer 14, third insulating layer 15 are thick semiconductor insulating material, wherein the first insulating layer is that heat is raw Long silica and silicon oxide deposition collectively constitute, and the thickness value of the first insulating layer is far below the half of the width value of wide groove Value, much larger than the value of the half of the width value of narrow groove；Second insulating layer be thermally grown formation silica, 500 nanometers of thickness More than, third insulating layer is to deposit the silica formed, 500 nanometers of thickness or more.The device architecture has two kinds of drift Area is moved, forms composite construction in parallel by the first insulator separation, the 6th semiconductor conducting layer of the device is partly led with third The PN junction that body conductive layer is formed, constitutes the first PN junction of device, and third semiconductor conducting layer is the first main drift of the first PN junction Area is N-type drift region；The PN junction that 5th semiconductor conducting layer and the 4th semiconductor conducting layer are formed, constitutes the 2nd PN of device Knot, the 5th semiconductor conducting layer are the second main drift region of the second PN junction, are P drift area, and cathodic region is that the 4th semiconductor is led Electric layer can provide how sub- carrier on direction of an electric field, improve in reversely restoring process in reversely restoring process, positive It is accumulated in the recombination rate of few sub- carrier in buffer layer when conducting, improves recombination velocity under equal conditions, reduces the anti-of device To recovery time.Structure illustrates the reversely restoring process of device of the present invention as shown in connection with fig. 2, when device anode applies positive voltage When, two PN junction positively biaseds of device form PN junction forward conduction, and form few sub- injection accumulation in respective drift region respectively, The drift region of first PN junction of device forms hole injection accumulation, and the drift region of the second PN junction forms electron injection accumulation, shape Sky at the accumulation respectively of two kinds of carriers, compared with the device of traditional single PN kink, under same current density, in unit volume The net injection accumulation density of cave and electronics offsets, and theoretically meeting has the characteristics that quick Reverse recovery is fast；When device is from just When to the process for being conducting to shutdown, i.e., after forward conduction again when anode applies negative voltage, the accumulation of the first PN junction drift region The electronics in hole and the accumulation of the second PN junction drift region, by being adulterated by heavy metal, capture trap, the electron-hole pair to be formed are multiple Fast quick-recovery under the action of reversed extraction under conjunction and backward voltage effect, in addition from the point of view of current-carrying subflow, electron stream is downward Direction, hole stream upward direction, under electric field action, the electronics in the 4th semiconductor conducting layer will go into the second semiconductor conduction In layer, electron hole pair recombination rate occurs for the hole for improving positive accumulation in the second semiconductor conducting layer；And the 5th semiconductor is led What is accumulated in electric layer is electronics, and since the mobility of electronics is much higher than hole mobility, the 5th semiconductor conducting layer is reversed Restore also fast, therefore, such structure of the invention, when there is lower Reverse recovery than the fast recovery diode of traditional structure Between, i.e., Reverse recovery is faster.Structure of the invention simultaneously uses the terminal protection of deep trench insulated layer, and area occupied is small, and Skin effect can be effectively reduced, leakage current is reduced, and breakdown electric field is introduced in vivo, breakdown voltage can be improved, just to optimization Adjustment space is provided to parameters such as pressure drop, breakdown reverse voltages, makes fast recovery diode of the invention that there is the more preferably figure of merit.

Fig. 3 to Fig. 9 shows the pilot process to form a kind of fast recovery diode with composite construction of the invention Diagrammatic cross-section can form the fast recovery diode device with composite construction of the invention by the manufacturing method that the present invention mentions Part illustrates graph structure in conjunction with Fig. 3 to Fig. 9, illustrates to form specific manufacturing method of the invention, specific manufacturing process is as follows:

A, it is silicon substrate with the first semiconductor conducting layer of the N-type of heavy doping 1, it is low that one layer of doping concentration is first generated by epitaxy technology In the second semiconductor conducting layer 2 of the N-type of silicon substrate concentration, then the extension by reducing doping concentration, form the third half of N-type Conductor conductive layer 3 forms thick second insulating layer 14, structure on the surface of third semiconductor conducting layer by thermally grown mode Figure is as shown in Figure 3；Using first time photoetching, etching, after etching 14 silicon oxide layer of second insulating layer, it is further continued for etching silicon, is carved The depth value for losing silicon is greater than 3 thickness value of third semiconductor conducting layer, leads less than third semiconductor conducting layer thickness value with the second half The sum of 2 thickness value of body conductive material designs the lines of different in width, forms the groove of different in width in reticle, at edge end Petiolarea forms narrow groove, and intermediate source region forms wide groove, and structure chart is as shown in Figure 4；

B, after by second of thermally grown one layer of silica, then the silicon oxide layer of a thickness is deposited, the first insulating layer is collectively formed 12, total thickness value is greater than more than half of narrow groove width value, and is less than the value of the half of the width value of wide groove, finally It is laterally filled up in narrow groove, wide groove does not fill up, only one layer of covering, i.e. the first insulating layer fills up narrow groove, covers wide channel side The state of one layer of wall and bottom, then by anisotropic etching, the first insulating layer of channel bottom is etched away, while by surface The first insulating layer etch away, structure is as shown in Figure 5；Again by epitaxial growth, time quarter, growing epitaxial silicon is repeated, returns and carved Journey grows the N-type silicon that doping concentration is higher than the second outer layer doping concentration in wide groove, and outer delay is by adjusting doped source The concentration distribution of the 4th semiconductor conducting layer is adjusted in concentration, so that in-between regional concentration is higher than the concentration of upper/lower terminal, most End form is less than trench depth value and third semiconductor at the 4th semiconductor conducting layer 11, the thickness value of the 4th semiconductor conducting layer The difference of the epitaxy layer thickness value of conductive layer, structure are as shown in Figure 6；Again by changing the type of the doped source of epitaxial process, after Quarter process is returned in the continuous epitaxial growth being repeated as many times, and low-doped P-type silicon is grown in wide groove, it is conductive to form the 5th semiconductor Layer 13, the 5th semiconductor conducting layer thickness stop outer when filling up the surface level of wide groove and third semiconductor conducting layer Prolong growth, return quarter process, since epitaxial process temperature is higher, and the doping concentration of the 4th semiconductor conducting layer is higher than the second half and leads The doping concentration of body conductive layer, therefore the impurity of the doping in the 4th semiconductor conducting layer can be spread downwards, formation is bent downwardly Doped interface, structure is as shown in Figure 7；

C, thick silica is deposited using deposit mode, forms third insulating layer, it, will using second of photoetching, corrosion process The second insulating layer of the intermediate area surface of device, third insulating layer erode, and structure is as shown in Figure 8；It is infused again by p type impurity Enter, knot, form the high concentration P-type silicon of certain depth, finally forms the 6th half on the third semiconductor conducting layer in source region Conductor conductive layer, the 7th semiconductor conducting layer of formation on the 5th semiconductor conducting layer, while the 4th semiconductor conducting layer are mixed Impurity will continue to slightly spread again downwards, forms curved surface distribution in channel bottom, forms the 4th final semiconductor conducting layer Region, then drift acid is carried out, the thin oxide layer formed in source region silicon face in knot process is eroded, it is conductive to expose the 6th semiconductor The silicon face of layer, the 7th semiconductor conducting layer, structure are as shown in Figure 9；

D, a thin layer platinum is overleaf sputtered or be deposited, then by short annealing, forms heavy metal platinum dopant, wet etching is gone Fall the platinum of excess surface；One layer of metal layer is formed in anode surface by the way of sputtering or evaporation again, using third Secondary photoetching, metal layer corrosion, form anode metal layer 18, by alloying, anode metal and the 6th semiconductor conducting layer, the 7th The surface of semiconductor conducting layer forms Ohmic contact；The lining of bottom is thinned using physical grinding mode, then carries out back-side gold Belong to layer sputtering or vapor deposition, forms back side cathode metal layer 19, ultimately form entire device architecture, structure is as shown in Figure 2.

The manufacturing method of a kind of fast recovery diode device with composite construction of the invention, it is characterised in that: pass through Insulator separation, then using epitaxial growth, time quarter, then epitaxial growth, the repetition epitaxial growth for returning quarter, fill groove；In extension When four semiconductor conducting layer of growth regulation, using the concentration of side doped source, the doping concentration for forming intermediate region is higher than upper and lower two The doping concentration of the doping concentration at end, the 4th semiconductor conducting layer doping concentration lowest part is higher than mixing for the second semiconductor conducting layer Miscellaneous concentration；Change the type of doped source, the 5th semiconductor conducting layer of the low doping concentration of growing P-type, in Reverse recovery again Prolonging direction of an electric field can provide more how sub- carriers, the recombination probability of the few sub- carrier accumulated when improving positive, therefore same Etc. under states, there is lower reverse recovery time；The 5th semiconductor conducting layer being additionally formed, makes device be provided with another kind The drift region of type is formed with the fast recovery diode device of the composite construction of two kinds of drift regions, and entire process flow 3 photoetching are only used, compared with the photoetching number of the fast recovery diode of traditional structure, a few polycrystalline photoetching reduces photoetching cost.

A kind of fast recovery diode with composite construction of the invention, the PN junction with two kinds of drift region, one Kind of PN junction is N-type drift region, a kind of PN junction is P drift area, the PN junctions of both drift regions by insulator separation formation every From parallel-connection structure, and the cathode in P drift area can along direction of an electric field when Reverse recovery for the N-type region of high concentration How sub- carrier is provided, accelerates the generation electron hole pair recombination rate of few sub- carrier accumulated when positive work, to be promoted Reverse recovery efficiency reduces reverse recovery time, realizes the effect for reducing switching power loss.

Fast recovery diode device with a kind of composite construction of the invention, compared with the fast recovery diode device of traditional structure Part has faster reverse recovery characteristic, therefore fast recovery diode device of the invention, has better figure of merit characteristic；It is practical The fast recovery diode device of the product of the invention of the equivalent specifications of manufacture, composite construction of the invention is faster than traditional structure The reverse recovery time of recovery diode is short by about 13%, improves the competitive advantage of product.

The present invention is elaborated through the foregoing embodiment, while can also realize the present invention using other embodiments.The present invention It is not limited to above-mentioned specific embodiment, therefore the present invention is limited by attached claim scope.