阅读说明：本技术 一种***栅4H-SiC VDMOS器件 (A kind of splitting bar 4H-SiC VDMOS device ) 是由 张有润 钟炜 王帅 杨啸 杨锐 罗佳敏 张波 于 2019-09-09 设计创作，主要内容包括：本发明涉及一种分裂栅4H-SiC VDMOS器件,属于功率半导体技术领域。本发明器件采用分离栅结构,在分离栅中间集成肖特基二极管,并且增加一个用于调整正向特性的第一N+区域。位于JFET区上方的肖特基接触在反向恢复过程中提供了一个电流通路,可以降低体二极管反向存储电荷,加快反向恢复过程；增加的第一N+区为器件正向偏置时提供了一个导电通道,降低器件的导通电阻,使其与传统器件保持一致。本发明的4H-SiC VDMOS结构具有更好的开关特性与反向恢复性能,并且可以保证静态特性与传统结构基本一致。(The present invention relates to a kind of splitting bar 4H-SiC VDMOS devices, belong to power semiconductor technologies field.Device of the present invention uses separate gate structures, the integrated schottky diode among separate gate, and increases by one for adjusting the first region N+ of forward characteristic.Schottky contacts above the area JFET provide a current path in reversely restoring process, can reduce body diode reverse storage charge, accelerate reversely restoring process；Increased first area N+ reduces the conducting resistance of device, is consistent it with traditional devices to provide a conductive channel when device forward bias.4H-SiC VDMOS structure of the invention has better switching characteristic and Reverse recovery performance, and can guarantee that static characteristic is almost the same with traditional structure.)

1. a kind of splitting bar 4H-SiC VDMOS device, comprising: drain electrode (1), N+ substrate (2), N- epitaxial layer (3), p-well (4), the One area N+ (5), N+ source region (6), the contact zone P+ (7), gate oxide (8), grid (9), Schottky contacts (10), source electrode (11), SiO₂Inter-level dielectric (12) and the area JFET (13)；

Drain electrode (1), N+ substrate (2) and N- epitaxial layer (3) are cascading from the bottom to top；

The area JFET (13) is located at the upper layer of N- epitaxial layer (3)；

P-well (4) is located at the upper layer of N- epitaxial layer (3) and is located at the two sides of the area JFET (13), and the first area N+ (5) interval is located at The upper layer in the area JFET (13), and it is located at the upper layer of p-well (4)；N+ source region (6) and the contact zone P+ (7) are located side by side at the upper of p-well (4) Layer, and the side positioned at the first area N+ (5) being spaced；

Gate oxide (8) is located in the part N+ source region (6) and the first area N+ (5) in the first area N+ (5)；

Grid (9) is located on gate oxide (8)；

SiO₂Inter-level dielectric (12) is located on gate oxide (8) and grid (9)；

Schottky contacts (10) are located on the area JFET (13)；

Source electrode (11) is located at the contact zone P+ (7) and the part N+ source region (6) far from the first area N+ (5), SiO₂Inter-level dielectric (12) and In Schottky contacts (10).

2. a kind of splitting bar 4H-SiC VDMOS device according to claim 1, which is characterized in that the first area N+ (5) by N ion implanting, junction depth is 0.2 μm~0.3 μm, doping concentration 1e17cm^-3。

3. a kind of splitting bar 4H-SiC VDMOS device according to claim 1, which is characterized in that the Schottky contacts (10) it is deposited by W metal and forms Schottky contacts, the width of Schottky contacts (10) is 2um.

4. a kind of splitting bar 4H-SiC VDMOS device according to claim 1, which is characterized in that the drain electrode (1) is adopted It is sputtered to form Ohmic contact with W metal.

5. a kind of splitting bar 4H-SiC VDMOS device according to claim 1, which is characterized in that the first area N+ (5) length is 2um, and the distance of the side far from N+ source region (6) to the area JFET (13) central point is 2um.

6. a kind of splitting bar 4H-SiC VDMOS device according to claim 1, which is characterized in that the first area N+ (5) distance of the side far from N+ source region (6) to Schottky contacts (10) close to the side in the first area N+ (5) is 1um.

7. a kind of splitting bar 4H-SiC VDMOS device according to claim 1, which is characterized in that the first area N+ (5) zone length overlapped with grid (9) is 0.5um.

8. a kind of splitting bar 4H-SiC VDMOS device according to claim 1, which is characterized in that the first area N+ (5) zone length overlapped with p-well (4) is 1.5um.

Technical field

The invention belongs to power semiconductor technologies fields, and in particular to a kind of splitting bar 4H-SiC VDMOS device.

Background technique

SiC material is the Typical Representative of third generation semiconductor material with wide forbidden band, due to its critical breakdown potential with higher Advantages such as field intensity, higher carrier saturation drift velocity, higher thermal conductivity and becoming make high-power, high temperature, high frequency, The ideal material of Flouride-resistani acid phesphatase device.

SiC power device achieves proud achievement by more than 20 years tremendous developments, as 600V, 1200V, 1700V, 3300V, 10kV SiC MOSFET element have been succeeded in developing, and 600V, 1200V, 1700V SiC MOSFET element are realized Commercialization.But there are also very big rooms for improvement for the power device of SiC material.By taking SiC MOSFET as an example, MOSFET grid leak electricity The size for holding Cgd affects the superiority and inferiority of MOSFET dynamic property, its switch performance can be optimized well by reducing Cgd, reduces dynamic Loss.The body diode reliability of MOSFET is lower, and MOSFET drain series diode is typically employed in engineering to prevent to post Then raw body diode current flow provides new freewheeling path in hourglass source electrode both ends additional inverse parallel Schottky diodes, it is clear that This method substantially increases the complexity and cost of circuit design.

Summary of the invention

The technical problem to be solved by the present invention is in view of the problems of the existing technology, provide a kind of splitting bar 4H-SiC VDMOS device.

In order to solve the above technical problems, the embodiment of the present invention provides a kind of splitting bar 4H-SiC VDMOS device, comprising: leakage Pole, N+ substrate, N- epitaxial layer, p-well, the first area N+, N+ source region, the contact zone P+, gate oxide, grid, Schottky contacts, source Pole, SiO₂Inter-level dielectric and the area JFET；

Drain electrode, N+ substrate and N- epitaxial layer are cascading from the bottom to top；

The area JFET is located at the upper layer of N- epitaxial layer；

P-well be located at the upper layer of N- epitaxial layer and be located at the area JFET two sides, the first section N+ every be located at the area JFET it is upper Layer, and it is located at the upper layer of p-well；N+ source region and the contact zone P+ are located side by side at the upper layer of p-well, and be spaced positioned at the one of the first area N+ Side；

Gate oxide is located in the part N+ source region and the first area N+ in the first area N+；

Grid is located on gate oxide；

SiO₂Inter-level dielectric is located on gate oxide and grid；

Schottky contacts are located in the area JFET；

Source electrode is located at the contact zone P+ and the part N+ source region far from the first area N+, SiO₂Inter-level dielectric and Schottky contacts On.

Based on the above technical solution, the present invention can also be improved as follows.

Further, the first area N+ is by N ion implanting, and junction depth is 0.2 μm~0.3 μm, doping concentration 1e17cm^-3。

Further, the Schottky contacts are deposited by W metal forms Schottky contacts, and the width of Schottky contacts is 2um。

Further, the drain electrode sputters to form Ohmic contact using W metal.

Further, the length in the first area N+ be 2um, the side far from N+ source region to JFET district center point away from From for 2um.

Further, side of the first area N+ far from N+ source region is to Schottky contacts close to the side in the first area N+ Distance is 1um.

Further, the zone length that the first area N+ and grid overlap is 0.5um.

Further, the zone length that the first area N+ and p-well overlap is 1.5um.

The beneficial effects of the present invention are: Schottky contacts and p-well play gate oxide when device is in blocking state Gate oxide electric field strength is effectively reduced in protective effect, to make device of the present invention relative to traditional 4H-SiC VDMOS structure Under the premise of forward characteristic and blocking characteristics are consistent, there is better dynamic characteristic.When device is in forward conduction, Due to the introducing in the first area N+, it is suppressed that p-well is to the pinch off effect of device, so that the ratio conducting resistance of device and traditional structure are protected It holds consistent.In addition, the separate gate structures that device of the present invention uses reduce Cgd, and the presence of Schottky contacts reduces body The reverse recovery charge of diode, dynamic property significantly improve.

Detailed description of the invention

Fig. 1 is a kind of structural schematic diagram of splitting bar 4H-SiC VDMOS device of the embodiment of the present invention；

Fig. 2 is the output of the splitting bar 4H-SiC VDMOS device of tradition 4H-SiC VDMOS device and the embodiment of the present invention Characteristic curve；

Fig. 3 is the breakdown of the splitting bar 4H-SiC VDMOS device of tradition 4H-SiC VDMOS device and the embodiment of the present invention Characteristic curve；

Fig. 4 is the capacitor of the splitting bar 4H-SiC VDMOS device of tradition 4H-SiC VDMOS device and the embodiment of the present invention Cgd is with drain voltage change curve；

Fig. 5 is the reversed of the splitting bar 4H-SiC VDMOS device of tradition 4H-SiC VDMOS device and the embodiment of the present invention Restoring current curve.

In attached drawing, parts list represented by the reference numerals are as follows:

1, it drains, 2, N+ substrate, 3, N- epitaxial layer, 4, p-well, the 5, the first area N+, 6, N+ source region, 7, the contact zone P+, 8, grid Oxide layer, 9, grid, 10, Schottky contacts, 11, source electrode, 12, SiO₂Inter-level dielectric, 13, the area JFET.

Specific embodiment

The principle and features of the present invention will be described below with reference to the accompanying drawings, and the given examples are served only to explain the present invention, and It is non-to be used to limit the scope of the invention.

As shown in Figure 1, a kind of splitting bar 4H-SiC VDMOS device provided in an embodiment of the present invention, comprising: drain electrode 1, N+ Substrate 2, N- epitaxial layer 3, p-well 4, the first area N+ 5, N+ source region 6, the contact zone P+ 7, gate oxide 8, grid 9, Schottky contacts 10, source electrode 11, SiO₂Inter-level dielectric 12 and the area JFET 13；

Drain electrode 1, N+ substrate 2 and N- epitaxial layer 3 are cascading from the bottom to top；

The area JFET 13 is located at the upper layer of N- epitaxial layer 3；

P-well 4 is located at the upper layer of N- epitaxial layer 3 and is located at the two sides in the area JFET 13, and the first area N+ 5 interval is located at the area JFET 13 upper layer, and it is located at the upper layer of p-well 4；N+ source region 6 and the contact zone P+ 7 are located side by side at the upper layer of p-well 4, and what is be spaced is located at the The side in one area N+ 5；

Gate oxide 8 is located in the part N+ source region 6 and the first area N+ 5 in the first area N+ 5；

Grid 9 is located on gate oxide 8；

SiO₂Inter-level dielectric 12 is located on gate oxide 8 and grid 9；

Schottky contacts 10 are located in the area JFET 13；

Source electrode 11 is located at the contact zone P+ 7 and the part N+ source region 6 far from the first area N+ 5, SiO₂Inter-level dielectric 12 and Xiao Te In base contact 10.

In above-described embodiment, drain electrode 1 is formed in N+ substrate back using the method for Ni metal sputtering；First area N+ 5, p-well 4, the mode that the contact zone P+ 7 and N+ source region 6 are all made of high temperature tension is formed；Source electrode 11 is using Ti Al metal sputtering Method is formed；Schottky contacts 10 are formed simultaneously with source electrode 11, and Schottky contacts 10 are directly contacted with N- epitaxial layer；Gate oxide 8 are formed by the way of the oxidation of hot oxygen；Grid 9 is formed by the way of polycrystalline silicon deposit；SiO₂Inter-level dielectric 12 is using deposit Mode formed.

Optionally, by N ion implanting, junction depth is 0.2 μm~0.3 μm in the first area N+ 5, and doping concentration is 1e17 cm^-3。

Optionally, the Schottky contacts 10 are deposited by W metal forms Schottky contacts, the width of Schottky contacts 10 For 2um.

Optionally, the drain electrode 1 sputters to form Ohmic contact using W metal.

Optionally, the length in the first area N+ 5 is 2um, the side far from N+ source region 6 to 13 central point of the area JFET Distance is 2um.

Optionally, side of the first area N+ 5 far from N+ source region 6 is to Schottky contacts 10 close to the one of the first area N+ 5 The distance of side is 1um.

Optionally, the first area N+ 5 and the zone length that grid 9 overlaps are 0.5um.

Optionally, the first area N+ 5 and the zone length that p-well 4 overlaps are 1.5um.

In order to illustrate the advantage of device dynamic characteristic of the present invention, it is done using 3300V SiC VDMOS as main device below Simulation analysis out.Its specific practice are as follows: the drain electrode 1 in VDMOS uses W metal；N+ substrate 2 is that concentration is 2E19cm^-3N-type Doping, N+ substrate 2 with a thickness of 4um；N- epitaxial layer 3 with a thickness of 30.25um；P-well 4 forms Gauss point using Al ion implanting Cloth, peak concentration 2e18cm^-3, peak concentration depth 0.5um；It adulterates to form box-shaped using N Lithium ions compensation in first area N+ 5 Distribution, concentration 1e18cm^-3；N+ source region 6 forms box-shaped distribution, concentration 2e19cm using N ion implanting^-3；P+ contact Area 7 forms box-shaped distribution, concentration 1e19cm using Al ion implanting^-3；Gate oxide 8 is silica, with a thickness of 2um；Schottky contacts 10 are formed using Ni Metal deposition, work function 4.9eV；Gate oxide 8 is by the way of the oxidation of hot oxygen It is formed；Grid 9 is formed on gate oxide 8 by the way of polycrystalline silicon deposit；SiO₂Inter-level dielectric 12 is using the side deposited Formula is formed between grid 9, source electrode 11 and Schottky contacts 10.

Device architecture as shown in Figure 1 is built using TCAD software Silvaco, in order to guarantee the structure of the embodiment of the present invention The static properties of device will not be generated and be significantly affected, carry out the structure and tradition VDMOS structure of the embodiment of the present invention below The comparison of static properties, including than conducting resistance and breakdown reverse voltage.As can be seen from Figure 2, traditional structure and structure of the invention More almost the same than conducting resistance, in Fig. 2, triangle legend curve and round legend curve respectively indicate traditional 4H-SiC VDMOS Device and splitting bar 4H-SiC VDMOS device of the invention, the drain current when grid voltage is 20V is with drain voltage change Curve, slope of a curve indicate the ratio conducting resistance of device.As can be seen from Figure 3, the reverse breakdown of traditional structure and structure of the invention For voltage all in 4600V or so, the breakdown potential of structure of the invention is pressed with small decline, but still reaches resistance to pressure request, in Fig. 3, Square legend curve indicates the breakdown characteristic of tradition 4H-SiC VDMOS device, and round legend curve table shows of the invention The breakdown characteristic of splitting bar 4H-SiC VDMOS device.

In the case where the two static parameter is almost the same, the capacitance characteristic of two kinds of structures is emulated, it is same to use Silvaco simulation software applies the AC signal of 10MHz, in drain voltage in 800V, as shown in figure 4, structure of the invention Cgd capacitor only has the half of traditional structure, and in Fig. 4, triangle legend curve and round legend curve respectively indicate traditional 4H- SiC VDMOS device and splitting bar 4H-SiC VDMOS device of the invention, in drain voltage from 0~800V, frequency 10MHz When, the curve of the capacitance with voltage variation of gate leakage capacitance.

Because structure of the invention introduces Schottky contacts 10 and carries out afterflow, Reverse recovery performance will have promotion.It is logical It crosses Slivaco software and carries out device circuitry hybrid simulation, as shown in figure 5, the reverse recovery time of structure of the invention can be learnt 50ns is shortened, maximum reverse restoring current reduces 40%, and reverse recovery charge reduces in 50%, Fig. 5, square legend Curve and round legend curve respectively indicate traditional 4H-SiC VDMOS device and splitting bar 4H-SiC VDMOS device of the invention Part, the curve that reverse recovery current changes over time.

In the description of the present invention, it is to be understood that, term " center ", " longitudinal direction ", " transverse direction ", " length ", " width ", " thickness ", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom" "inner", "outside", " up time The orientation or positional relationship of the instructions such as needle ", " counterclockwise ", " axial direction ", " radial direction ", " circumferential direction " be orientation based on the figure or Positional relationship is merely for convenience of description of the present invention and simplification of the description, rather than the device or element of indication or suggestion meaning must There must be specific orientation, be constructed and operated in a specific orientation, therefore be not considered as limiting the invention.

In addition, term " first ", " second " are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance Or implicitly indicate the quantity of indicated technical characteristic.Define " first " as a result, the feature of " second " can be expressed or Implicitly include at least one this feature.In the description of the present invention, the meaning of " plurality " is at least two, such as two, three It is a etc., unless otherwise specifically defined.

In the present invention unless specifically defined or limited otherwise, term " installation ", " connected ", " connection ", " fixation " etc. Term shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integral；It can be mechanical connect It connects, is also possible to be electrically connected；It can be directly connected, can also can be in two elements indirectly connected through an intermediary The interaction relationship of the connection in portion or two elements, unless otherwise restricted clearly.For those of ordinary skill in the art For, the specific meanings of the above terms in the present invention can be understood according to specific conditions.

In the present invention unless specifically defined or limited otherwise, fisrt feature in the second feature " on " or " down " can be with It is that the first and second features directly contact or the first and second features pass through intermediary mediate contact.Moreover, fisrt feature exists Second feature " on ", " top " and " above " but fisrt feature be directly above or diagonally above the second feature, or be merely representative of First feature horizontal height is higher than second feature.Fisrt feature can be under the second feature " below ", " below " and " below " One feature is directly under or diagonally below the second feature, or is merely representative of first feature horizontal height less than second feature.

In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example Point is included at least one embodiment or example of the invention.In the present specification, schematic expression of the above terms are not It must be directed to identical embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be in office It can be combined in any suitable manner in one or more embodiment or examples.In addition, without conflicting with each other, the skill of this field Art personnel can tie the feature of different embodiments or examples described in this specification and different embodiments or examples It closes and combines.

The foregoing is merely presently preferred embodiments of the present invention, is not intended to limit the invention, it is all in spirit of the invention and Within principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.