阅读说明：本技术 低功耗高可靠性的沟槽型碳化硅mosfet器件 (The groove-shaped silicon carbide MOSFET device of low power consumption and high reliability ) 是由 李轩 徐晓杰 黄伟 陈致宇 邓小川 张波 于 2019-09-07 设计创作，主要内容包括：本发明提供一种低功耗高可靠性的沟槽型碳化硅MOSFET器件,包括：N型衬底、N型外延层、第一P-body区、第一P+接触区、第一N+接触区、第二P-body区、第二P+接触区、第二N+接触区、氧化层、槽栅、金属电极、漏极；本发明提出的SiC MOSFET器件通过4沟道并联显著减小导通电阻,通过第二P-body对栅槽的包裹及保护,既增强了器件的氧化层可靠性,又屏蔽了部分栅漏电容使得器件开关损耗减小；当器件发生短路时,第一P-body区与第二P-body区形成的JFET区夹断,降低了器件的饱和电流,提高了其短路能力。(The present invention provides a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability, comprising: N-type substrate, N-type epitaxy layer, the first area P-body, the first contact zone P+, the first contact zone N+, the 2nd area P-body, the 2nd contact zone P+, the 2nd contact zone N+, oxide layer, slot grid, metal electrode, drain electrode；SiC MOSFET element proposed by the present invention is substantially reduced conducting resistance by 4 channels connected in parallel, and package and protection by the 2nd P-body to grid slot had not only enhanced the oxide layer reliability of device, but also shields part gate leakage capacitance and devices switch loss is reduced；When short circuit occurs for device, the area the JFET pinch off that the first area P-body and the 2nd area P-body are formed reduces the saturation current of device, improves its short-circuit capacity.)

1. a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability, characterized by comprising: N-type substrate (11), N-type epitaxy layer (10) above N-type substrate (11), the 2nd area P-body (9) above N-type epitaxy layer (10), position In the 2nd internal contact zone P+ (7) of the 2nd area P-body (9) and the 2nd contact zone N+ (8), positioned at the 2nd contact zone P+ (7) and Source electrode (1) above 2nd contact zone N+ (8), gate medium (6) and gate medium (6) above the 2nd contact zone N+ (8) The slot grid (2) of inside, the first area P-body (5) between gate medium (6), two above the first area P-body (5) The first contact zone P+ (3) between a first contact zone N+ (4), two the first contact zones N+ (4) is located at the first contact zone P+ (3) and source electrode (1) above the first contact zone N+ (4), it is located at below device and forms Ohmic contact with N-type substrate (11) It drains (12)；Source electrode (1) connects with the first contact zone P+ (3), the first contact zone N+ (4), the 2nd contact zone P+ (7), the 2nd N+ Touch area (8) Ohmic contact.

2. a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability according to claim 1, feature exist In: the slot grid (2) are inverted L-shaped with gate medium (6), and the inverted L-shaped includes the vertical of connection below horizontal segment and horizontal segment Section is equipped with N-type epitaxy layer (10) between the first area P-body (5) and two sides gate medium (6), the slot grid (2) and gate medium (6) Horizontal segment is located above the first contact zone N+ (4), the first area P-body (5) and N-type epitaxy layer (10), slot grid (2) and the first N+ Contact zone (4), the first area P-body (5) are designed with gate medium (6) between N-type epitaxy layer (10).

3. a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability according to claim 1, feature exist In: it is equipped with 2 the first areas P-body (5) between gate medium (6), sets that there are two the first P+ between two the first contact zones N+ (4) Contact zone (3) is designed with N-type epitaxy layer between two the first contact zones P+ (3) and two the first areas P-body (5) (10), N-type epitaxy layer (10) and source electrode (1) form Schottky contacts.

4. a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability according to claim 1, feature exist In: the left and right sides in the 2nd area P-body (9) is N-type epitaxy layer (10), and N-type epitaxy layer (10) and source electrode (1) form Xiao Te Base contact.

5. a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability according to claim 1, feature exist In: it is N-type epitaxy layer (10), the first contact zone N+ (4), the first P- between the first area P-body (5) and two sides gate medium (6) The area body (5) and N-type epitaxy layer (10), three are equipped with gate medium (6) between source electrode (1).

6. a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability described in any one according to claim 1~5 Part, it is characterised in that: the gate medium (6) is SiO₂。

7. a kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability described in any one according to claim 1~5 Part, it is characterised in that: each doping type accordingly becomes opposite doping in the device, i.e. p-type doping becomes the same of n-type doping When n-type doping become p-type doping.

Technical field

The invention belongs to power semiconductor device technology field, the groove-shaped carbonization of specifically a kind of low power consumption and high reliability Silicon MOSFET element.

Background technique

One of representative as third generation semiconductor material with wide forbidden band, silicon carbide (Silicon Carbide) material have Forbidden bandwidth is big (3.26eV), critical electric field height (3 × 10⁶V/cm), carrier saturation drift velocity height (2 × 10⁷Cm/s), hot Conductance height (490W/Mk), the advantages that thermal stability is good, are to prepare the excellent material of high voltage electric and electronic device, high-power, high Temperature, high pressure and Flouride-resistani acid phesphatase field of power electronics have broad application prospects.

MOSFET is most widely used a kind of gate controlled device structure in silicon carbide power device.Due to silicon carbide MOSFET be by monopole transport working mechanism with the characteristics of device, only one of electronics or hole current-carrying subconductivity do not have Charge-storage effect, therefore have lower switching loss and higher frequency characteristic compared to bipolar devices, along with its is low Conducting resistance and excellent hot properties so that silicon carbide MOSFET is become the low-loss power device of the great competitiveness of a new generation Part.Current commercialized silicon carbide MOSFET there are two main classes structure: groove gate type and plane.Plane is due to technique essence Degree limitation, conducting resistance is larger and integrated level is lower.Groove profile silicon carbide MOSFET effectively improves gully density using slot grid, It is the important developing direction of next-generation silicon carbide MOSFET.

Silicon carbide tank gate MOSFET is born higher anti-in reverse operation by the depletion region formed in the drift region N- To bias, due to the high critical breakdown electric field of carbofrax material, the position of the drift region bottom Cao Shan can reach when closing on breakdown Very high electric field.Since the dielectric constant of oxide layer is less than carbofrax material, electric field strength is about the 2.8 of silicon carbide Times, along with curvature effect makes oxide layer turning assemble high electric field, working long hours will lead to grid oxygen under high electric field Change layer to degenerate, reliability decrease.The electric field strength of oxide layer when in order to reduce device reverse operation, that improves oxide layer can By property, a kind of common solution is to introduce P+ shielded layer in trench oxide layer bottom to weaken the electric-field strength of slot gate oxide Degree.Although the P+ shielded layer positioned at slot grid bottom can make the oxide layer of slot grid bottom and corner obtain protecting more by force, slot The oxide layer of side wall still will receive the potential challenge of high electric field in blocking state, therefore the introducing of P+ shielded layer can not be fully solved The integrity problem that slot gate oxide is impacted by high electric field.

Since current carbofrax material and the poor interfacial state of grid oxygen medium result in too low channel mobility, groove gate type Silicon carbide MOSFET on state characteristic compares also biggish distance with theoretical limit.Due to groove gate type silicon carbide MOSFET grid leak electricity Hold larger, switching loss is higher.Simultaneously as its current saturation electric current is higher, short-circuit capacity is weaker.

Summary of the invention

The purpose of the present invention is to propose to a kind of groove-shaped silicon carbide MOSFET devices of low power consumption and high reliability, pass through One, package and protection of two P-body to slot grid enhances the reliability of oxide layer especially side grid oxygen in entire slot, shielding Part gate leakage capacitance reduces the switching loss of device.Since the first and second area P-body makees the shielding of trench ends electric field With the channel of device can shorten, and 4 such short channel parallel connections substantially reduce device channel resistance.When device occurs When short-circuit, device is in high-voltage great-current state, the area JFET formed at this time by the first area P-body and the 2nd area P-body And the 2nd the area the JFET pinch off that is formed between the area P-body be saturated device current in advance, improve the short-circuit capacity of device, Further improve the reliability of device.

For achieving the above object, technical solution of the present invention is as follows:

A kind of groove-shaped silicon carbide MOSFET device of low power consumption and high reliability, comprising: N-type substrate 11 is located at N-type substrate The N-type epitaxy layer 10 of 11 tops, is located inside the 2nd area P-body 9 the 2nd area P-body 9 above N-type epitaxy layer 10 The 2nd contact zone P+ 7 and the 2nd contact zone N+ 8, the source electrode 1 above the 2nd contact zone P+ 7 and the 2nd contact zone N+ 8, Slot grid 2 inside the gate medium 6 and gate medium 6 above the 2nd contact zone N+ 8, the first P- between gate medium 6 The first P between the area body 5, the first contact zone N+ 4 of two the first contact zones N+ 4, two above the first area P-body 5 + contact zone 3, the source electrode 1 above the first contact zone P+ 3 and the first contact zone N+ 4 are located at below device and serve as a contrast with N-type The drain electrode 12 of the formation of bottom 11 Ohmic contact；Source electrode 1 and the first contact zone P+ 3, the first contact zone N+ 4, the 2nd contact zone P+ 7, 2nd contact zone N+, 8 Ohmic contact.

It is preferred that the slot grid 2 and gate medium 6 are inverted L-shaped, the inverted L-shaped includes horizontal segment and horizontal segment The vertical section of lower section connection, is equipped with N-type epitaxy layer 10 between the first area P-body 5 and two sides gate medium 6, the slot grid 2 are situated between with grid The horizontal segment of matter 6 is located at 10 top of the first contact zone N+ 4, the first area P-body 5 and N-type epitaxy layer, and slot grid 2 are contacted with the first N+ Area 4, the first area P-body 5 are designed with gate medium 6 between N-type epitaxy layer 10.

It is preferred that being equipped with 2 the first areas P-body 5 between gate medium 6, set between two the first contact zones N+ 4 There are two the first contact zone P+ 3, it is designed with outside N-type between two the first contact zones P+ 3 and between two the first areas P-body 5 Prolong layer 10, N-type epitaxy layer 10 and source electrode 1 form Schottky contacts.

It is preferred that the left and right sides in the 2nd area P-body 9 is N-type epitaxy layer 10, N-type epitaxy layer 10 and source electrode 1 forms Schottky contacts.

It is preferred that being N-type epitaxy layer 10, the first N+ contact between the first area P-body 5 and two sides gate medium 6 Area 4, the first area P-body 5 and N-type epitaxy layer 10, three are equipped with gate medium 6 between source electrode 1.

It is preferred that the gate medium is SiO₂。

It is preferred that each doping type accordingly becomes opposite doping in the device, i.e. p-type doping becomes N-type N-type doping becomes p-type doping while doping.

Device material therefor is SiC material, can also be other semiconductor materials.

The invention has the benefit that 1: SiC MOSFET element proposed by the present invention is substantially reduced by 4 channels connected in parallel Conducting resistance；2: package and protection by the 2nd P-body to grid slot enhance the oxide layer reliability of device, shielded segment Gate leakage capacitance is to reduce devices switch loss.3: when short circuit occurs for device, the first area P-body and the 2nd area P-body shape At the area JFET pinch off, reduce saturation current, improve the short-circuit capacity of device.

Detailed description of the invention

Fig. 1 is traditional Si C Grooved-gate MOSFET's device junction composition；

Fig. 2 is the device junction composition of the embodiment of the present invention 1；

Fig. 3 is the device junction composition of the embodiment of the present invention 2；

Fig. 4 is the device junction composition of the embodiment of the present invention 3；

Fig. 5 is the device junction composition of the embodiment of the present invention 4；

Fig. 6 is the device junction composition of the embodiment of the present invention 5；

1 it is source electrode, 2 be slot grid, 3 be the first contact zone P+, 4 be the first contact zone N+, 5 be the first area P-body, 6 is Gate medium, 7 be the 2nd contact zone P+, 8 be the 2nd contact zone N+, 9 be the 2nd area P-body, 10 be N-type epitaxy layer, 11 be N-type Substrate, 12 be drain electrode, 13 be P+ shielded layer.

Specific embodiment

Illustrate embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this specification Other advantages and efficacy of the present invention can be easily understood for disclosed content.The present invention can also pass through in addition different specific realities The mode of applying is embodied or practiced, the various details in this specification can also based on different viewpoints and application, without departing from Various modifications or alterations are carried out under spirit of the invention.