CN107507861A - Enhanced SiC PNM IGBT devices and preparation method thereof are injected in Novel Schottky contact - Google Patents

Enhanced SiC PNM IGBT devices and preparation method thereof are injected in Novel Schottky contact Download PDF

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CN107507861A
CN107507861A CN201710466243.8A CN201710466243A CN107507861A CN 107507861 A CN107507861 A CN 107507861A CN 201710466243 A CN201710466243 A CN 201710466243A CN 107507861 A CN107507861 A CN 107507861A
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layer
drift layer
groove
oxide layer
emitter stage
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CN201710466243.8A
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CN107507861B (en
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张玉明
姜珊
张艺蒙
宋庆文
汤晓燕
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西安电子科技大学
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof; Multistep manufacturing processes therefor
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/70Bipolar devices
    • H01L29/72Transistor-type devices, i.e. able to continuously respond to applied control signals
    • H01L29/739Transistor-type devices, i.e. able to continuously respond to applied control signals controlled by field-effect, e.g. bipolar static induction transistors [BSIT]
    • H01L29/7393Insulated gate bipolar mode transistors, i.e. IGBT; IGT; COMFET
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof; Multistep manufacturing processes therefor
    • H01L29/02Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/12Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/24Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof; Multistep manufacturing processes therefor
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007Multistep manufacturing processes
    • H01L29/66075Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66234Bipolar junction transistors [BJT]
    • H01L29/66325Bipolar junction transistors [BJT] controlled by field-effect, e.g. insulated gate bipolar transistors [IGBT]

Abstract

The present invention relates to a kind of contact of Novel Schottky to inject enhanced SiC PNM IGBT device its preparation methods.The preparation method includes:Transition zone, the first drift layer, cushion, current collection layer are continuously grown in SiC substrate;Etch the first drift layer and form first groove, deposit the first oxide layer;The drift layer of growth regulation two;The growing P-type well region on the second drift layer, P+ doped regions, P contact zones and N+ launch sites are formed in P type trap zone;Etching prepares second groove, forms buries oxide layer;In second groove growth regulation dioxide layer, depositing polysilicon;Deposited metal forms emitter stage Ohm contact electrode, emitter stage Schottky contact electrode and emitter contact electrode respectively.The present invention introduces buries oxide layer in groove grid both sides, and introduces Schottky contact electrode in emitter stage and enhance conductivity modulation effect, reduces conducting resistance, the turn-off time can't be caused to significantly increase, and compatible with existing process in technique.

Description

Enhanced SiC PNM-IGBT devices and preparation method thereof are injected in Novel Schottky contact

Technical field

The present invention relates to technical field of integrated circuits, enhanced SiC is injected in more particularly to a kind of Novel Schottky contact PNM-IGBT devices and preparation method thereof.

Background technology

With the continuous improvement of demand and the efficiency requirement of electronic product, power device plays more and more important work With.Almost being used for all electronics manufacturings includes computer realm, network communication field, consumer electronics field, Industry Control The various equipment in field.Chinese power device market is always maintained at faster development speed, and China's New Type Power Devices mainly have VDMOS and IGBT class devices, and new material power device mainly has SiC and GaN device.SiC is typical wide bandgap semiconductor Material, with energy gap is big, critical electric field is high, carrier saturation velocity is high, physicochemical properties are stable, hardness is high, heat is steady The features such as qualitative good and thermal conductivity is high, it is highly suitable for making high temperature, radioresistance, high frequency, high-power and High Density Integration work( Rate device.IGBT (Insulated Gate Bipolar Transistor), insulated gate bipolar transistor, is in MOSFET With a kind of NEW TYPE OF COMPOSITE power device to grow up on the basis of BJT, the advantages of being compounded with the two, there is MOS inputs, bipolar defeated Go out function, collection BJT device on-state voltage drops are small, current carrying density is big, high pressure and power MOSFET driving powers are small, switching speed Hurry up, the advantages of input impedance is high, heat endurance is good.

SiC IGBT combine the characteristics of low in energy consumption, breakdown voltage is high, switching speed is fast, relative to SiC MOSFET and The devices such as the IGBT of silicon substrate, IGCT have significant advantage, especially suitable for high temperature, high pressure, high frequency, high-power electric system Application field.SiC MOS devices have released the device of high-breakdown-voltage and interface state density, and the development for being SiC IGBT is created Condition.In recent years, with energy-saving and emission-reduction dynamics continue to increase and the continuous development of new energy field, IGBT are high as energy-conservation Effect device has broader development space.

As other power devices, SiC IGBT are primarily upon the influence of power consumption and voltage.In order to reduce the work(of device Consumption, can reduce conducting resistance, therefore it is required that the drift region of device has the free carrier of higher concentration in on-state.However, Substantial amounts of free carrier can cause device to have the longer turn-off time, increase the turn-off power loss of device, cause conducting resistance Contradiction between turn-off power loss.

The content of the invention

Therefore, to solve technological deficiency and deficiency existing for prior art, the present invention proposes a kind of enhanced SiC of injection PNM-IGBT devices and preparation method thereof.

Specifically, the preparation side for the enhanced SiC PNM-IGBT devices of a kind of injection that one embodiment of the invention proposes Method, including:

Using hot wall LPCVD techniques transition zone, the first drift layer, cushion, current collection layer are continuously grown in SiC substrate;

First drift layer is etched using reactive ion etching process, first groove is formed, is existed using thermal oxidation technology The oxide layer of first groove growth regulation one;

Using hot wall LPCVD techniques in the second drift layer of first drift layer and the first oxide layer superficial growth;

Using hot wall LPCVD techniques in the second drift layer growing P-type well region;

Using ion implantation technology P+ doped regions, P contact zones and N+ launch sites are formed in the P type trap zone;

Etch second drift layer and first oxide layer using reactive ion etching process, formed second groove with Prepare buries oxide layer;

Using thermal oxidation technology in the second groove growth regulation dioxide layer, using CVD techniques in the described second oxidation Layer growing polycrystalline silicon;

Deposited metal forms emitter stage Ohm contact electrode, emitter stage Schottky contact electrode and collector contact electricity Pole.

In one embodiment of the invention, using thermal oxidation technology in the oxide layer of first groove growth regulation one, bag Include:

The first oxide layer described in continued propagation in the first groove, until first oxide layer depth with it is described First drift layer is concordant;

Remove first oxide layer on first drift layer;

Planarization process is carried out to first oxide layer and first drift layer.

In one embodiment of the invention, using thermal oxidation technology the oxide layer of first groove growth regulation one it Before, in addition to:

Using CMP, the SiC substrate and the transition zone are removed.

In one embodiment of the invention, using hot wall LPCVD techniques in the second drift layer growing P-type well region, Including:

Using hot wall LPCVD techniques second drift layer growth depth be 0.5~2 μm, Al-doping concentration be 1 ×1017~1 × 1018cm-3The P type trap zone.

In one embodiment of the invention, connect using ion implantation technology in P type trap zone formation P+ doped regions, P Area and N+ launch sites are touched, including:

Using ion implantation technology the P type trap zone formed depth be 0.1~0.5 μm, Al-doping concentration be 1 × 1019~1 × 1021cm-3The P+ doped regions;

Using ion implantation technology the P type trap zone formed depth be 0.01~0.1 μm, Al-doping concentration be 2 ×1017~1 × 1018cm-3The P contact zones;

Using ion implantation technology the P type trap zone formed depth be 0.1~0.5 μm, Nitrogen ion doping concentration be 1 × 1018~1 × 1020cm-3The N+ launch sites.

In one embodiment of the invention, the width of the second groove is less than the width of the first groove.

In one embodiment of the invention, deposited metal forms emitter stage Ohm contact electrode, including:

Photoresist is deposited in whole device surface, development forms emitter stage metal ohmic contact window, in whole device table Face deposits Ni/Ti/Al alloys, and emitter stage ohmic contact metal layer is formed using ultrasonic wave stripping technology;

At a temperature of 900 DEG C, annealed 5 minutes in nitrogen atmosphere, form the emitter stage Ohm contact electrode.

In one embodiment of the invention, deposited metal forms emitter stage Schottky contact electrode, including:

Photoresist is deposited in whole device surface, development forms emitter stage Schottky contact metal window, in whole device Surface deposition W metal, the emitter stage Schottky contact electrode is formed using ultrasonic wave stripping technology.

In one embodiment of the invention, deposited metal forms emitter contact electrode, including:

Ti/Al alloys are deposited in the current collection layer lower surface, form collector contact metal;

At a temperature of 1050 DEG C, annealed 3 minutes in nitrogen atmosphere and form the emitter contact electrode.

One kind that further embodiment of the present invention proposes injects enhanced SiC PNM-n-IGBT devices, including:Current collection layer, Cushion, drift layer, P type trap zone, P+ doped regions, P contact zones, N+ launch sites, buries oxide layer, emitter stage Ohm contact electrode, Emitter stage Schottky contact electrode, emitter contact electrode, wherein, the buries oxide layer is located in the drift layer, the note Enter enhanced SiC PNM-IGBT devices and prepared as the method described in above-described embodiment to be formed.

By the detailed description below with reference to accompanying drawing, other side of the invention and feature become obvious.But it should know Road, the accompanying drawing is only the purpose design explained, not as the restriction of the scope of the present invention, because it should refer to Appended claims.It should also be noted that unless otherwise noted, it is not necessary to which scale accompanying drawing, they only try hard to concept Ground illustrates structure and flow described herein.

Brief description of the drawings

Below in conjunction with accompanying drawing, the embodiment of the present invention is described in detail.

Fig. 1 is a kind of process chart for injecting enhanced SiC PNM-IGBT devices provided in an embodiment of the present invention;

Fig. 2 is a kind of schematic diagram for injecting enhanced SiC PNM-n-IGBT devices provided in an embodiment of the present invention;

Fig. 3 a- Fig. 3 q are a kind of technique for injecting enhanced SiC PNM-n-IGBT devices provided in an embodiment of the present invention Schematic diagram;

Fig. 4 is a kind of schematic diagram for injecting enhanced SiC PNM-p-IGBT devices provided in an embodiment of the present invention;

Fig. 5 a- Fig. 5 n are a kind of technique for injecting enhanced SiC PNM-p-IGBT devices provided in an embodiment of the present invention Schematic diagram.

Embodiment

In order to facilitate the understanding of the purposes, features and advantages of the present invention, below in conjunction with the accompanying drawings to the present invention Embodiment be described in detail.

Embodiment one

Fig. 1 is referred to, Fig. 1 injects enhanced SiC PNM- for a kind of Novel Schottky contact provided in an embodiment of the present invention The process chart of IGBT device.This method comprises the following steps:

Step a, using hot wall LPCVD techniques the SiC substrate continuously grow transition zone, the first drift layer, cushion, Current collection layer;

Step b, first drift layer is etched using reactive ion etching process, forms first groove, utilize thermal oxide Technique is in the oxide layer of first groove growth regulation one;

Step c, floated using hot wall LPCVD techniques in first drift layer and the first oxide layer superficial growth second Move layer;

Step d, using hot wall LPCVD techniques in the second drift layer growing P-type well region;

Step e, P+ doped regions, P contact zones and N+ launch sites are formed in the P type trap zone using ion implantation technology;

Step f, second drift layer and first oxide layer are etched using reactive ion etching process, forms second Groove is to prepare buries oxide layer;

Step g, using thermal oxidation technology in the second groove growth regulation dioxide layer, using CVD techniques described Dioxide layer growing polycrystalline silicon;

Step h, deposited metal forms emitter stage Ohm contact electrode, emitter stage Schottky contact electrode and current collection respectively Pole contacts electrode;

Wherein, for step b, can include:

The first oxide layer described in continued propagation in the first groove, until first oxide layer depth with it is described First drift layer is concordant;

Remove first oxide layer on first drift layer;

Planarization process is carried out to first oxide layer and first drift layer.

Further, before step b, can also include:

Using CMP, the SiC substrate and the transition zone are removed.

Wherein, for step d, can include:

Using hot wall LPCVD techniques second drift layer growth depth be 0.5~2 μm, Al-doping concentration be 1 ×1017~1 × 1018cm-3The P type trap zone.

Wherein, for step e, can include:

Using ion implantation technology the P type trap zone formed depth be 0.1~0.5 μm, Al-doping concentration be 1 × 1019~1 × 1021cm-3The P+ doped regions;

Using ion implantation technology the P type trap zone formed depth be 0.01~0.1 μm, Al-doping concentration be 2 ×1017~1 × 1018cm-3The P contact zones;

Using ion implantation technology the P type trap zone formed depth be 0.1~0.5 μm, Nitrogen ion doping concentration be 1 × 1018~1 × 1020cm-3The N+ launch sites.

Wherein, for second groove in step f, can include:

The width of the second groove is less than the width of the first groove.

Wherein, emitter stage Ohm contact electrode is formed for deposited metal in step h, can included:

Photoresist is deposited in whole device surface, development forms emitter stage metal ohmic contact window, in whole device table Face deposits Ni/Ti/Al alloys, and emitter stage ohmic contact metal layer is formed using ultrasonic wave stripping technology;

At a temperature of 900 DEG C, annealed 5 minutes in nitrogen atmosphere, form the emitter stage Ohm contact electrode.

Wherein, emitter stage Schottky contact electrode is formed for deposited metal in step h, can included:

Photoresist is deposited in whole device surface, development forms emitter stage Schottky contact metal window, in whole device Surface deposition W metal, the emitter stage Schottky contact electrode is formed using ultrasonic wave stripping technology.

Wherein, emitter contact electrode is formed for deposited metal in step h, can included:

Ti/Al alloys are deposited in the current collection layer lower surface, form collector contact metal;

At a temperature of 1050 DEG C, annealed 3 minutes in nitrogen atmosphere and form the emitter contact electrode.

The present embodiment, by above-mentioned processing technology, at least possesses following advantage:

1), the introducing of buries oxide layer equivalent to by gate bottom overstriking, brings bottleneck effect in the present invention, and it is empty to play stop The effect in cave, enhances conductivity modulation effect, device is had less conduction voltage drop under high current, and due to being sent out during shut-off The carrier of emitter-base bandgap grading side can be scanned out rapidly under forceful electric power field action, the turn-off time can't be caused to significantly increase.

2), Schottky barrier has raised the potential of base in the present invention, plays a part of stopping hole, enhances conductance tune Effect processed, make device that there is less conduction voltage drop under high current, and due to the positive guide of Schottky diode exponential form Logical characteristic, does not increase turn-off power loss.

3), compared to other, for enhancing conductance modulation, improved new construction, new construction proposed by the present invention are manufacturing work Compatible with traditional handicraft in skill, feasibility is higher.

Embodiment two

Fig. 2 is referred to, Fig. 2 injects enhanced SiC PNM- for a kind of Novel Schottky contact provided in an embodiment of the present invention The schematic diagram of n-IGBT devices.

Device architecture includes current collection layer 201, cushion 202, drift layer 203, P type trap zone 204, P+ doped regions 205, P and connect Touch area 206, N+ launch sites 207, buries oxide layer 208, emitter stage Ohm contact electrode 209, emitter stage Schottky contact electrode 210 With emitter contact electrode 211, wherein, the buries oxide layer 208 is located in drift layer.

Preferably, current collection layer 201 is P+ current collection layers, and cushion 202 is N+ cushions, and drift layer 203 is N- drift layers.

The present invention working principle and beneficial effect be specially:

The present invention proposes a kind of Novel Schottky contact and injects enhanced SiC PNM-IGBT devices.With traditional Si C IGBT is compared, and the present invention introduces buries oxide layer in groove grid both sides, equivalent to by gate bottom overstriking, due to bottleneck effect, makes device Part plays a part of stopping hole in the case where that need not reduce groove grid spacing, so as to enhance conductivity modulation effect, reduces Conducting resistance, the carrier of emitter stage side can be scanned out rapidly under forceful electric power field action during due to shut-off, can't be led The turn-off time is caused to significantly increase, and it is compatible with existing process in technique.

In addition, emitter stage contact electrode is divided into two parts, metal and N+ launch sites contact portion are Ohmic contact, metal It is Schottky contacts with P contact zones contact portion.Schottky barrier has raised the potential of P type trap zone, plays the work for stopping hole With so as to enhance conductivity modulation effect, reducing the resistance of N- drift regions, device is had under high current and less lead Logical pressure drop.In turn off process, grid voltage is gradually reduced to 0, and as electric current is gradually reduced, device partial pressure becomes larger, due to Xiao Te The forward conduction characteristic of based diode exponential form, will not hinder hole to flow out, and make hole outflow on the contrary faster, so will not increase Add the turn-off time, switching loss can be reduced on the contrary.One layer of intermediate concentration doping P contact zone is provided between P+ doped regions and metal, By the way that ion implantation energy and depth regulation and control can be achieved, making intermediate concentration doping P contact zones is more managed to be formed The Schottky contacts thought.

Embodiment three

Fig. 3 a- Fig. 3 q, Fig. 3 a- Fig. 3 q are referred to for a kind of Novel Schottky contact injection provided in an embodiment of the present invention to increase The process schematic representation of strong type SiC PNM-n-IGBT devices, on the basis of above-described embodiment, the present embodiment will in more detail Technological process to the present invention is introduced.This method includes:

S301, N+SiC substrates 001 are chosen, RCK standard cleanings are carried out to N+SiC substrates 301, as shown in Figure 3 a;

S302, using hot wall LPCVD techniques in the growth thickness of N+SiC substrates 301 it is 10~30 μm of transition zone 302, its In, the thickness of transition zone 302 is also an option that 20 μm, as shown in Figure 3 b;

S303, using hot wall LPCVD techniques, epitaxial thickness is 100~200 μm on transition zone 302, and Nitrogen ion doping is dense Spend for 1 × 1014~1 × 1015cm-3The first drift layer 303, wherein the thick bottom of the first drift layer 303 is also an option that 135 μ M, Nitrogen ion doping concentration are also an option that 2 × 1014cm-3, as shown in Figure 3 c;

S304, using hot wall LPCVD techniques the epitaxial thickness of the first drift layer 303 be 1~10 μm, Nitrogen ion doping concentration 1×1016~1 × 1018cm-3Cushion 304, the thickness of wherein cushion 304 is also an option that 3 μm, Nitrogen ion doping concentration It is also an option that 1 × 1017cm-3, as shown in Figure 3 d;

S305, using hot wall LPCVD techniques the epitaxial thickness of cushion 304 be 3~5 μm, Al-doping concentration 1 × 1018~1 × 1020cm-3Current collection layer 305, wherein aluminum ions doping concentration is also an option that 1 × 1019cm-3, such as Fig. 3 e institutes Show;

S306, using CMP, remove SiC substrate 301 and transition zone 302, as illustrated in figure 3f;

S307, using reactive ion etching process etch the first drift layer 303, formed first groove 306, depth be 1~ 10 μm, as shown in figure 3g;

S308, using thermal oxidation technology first groove 306 deposit the first oxide layer 307, grind off on the first drift layer Oxide, only retain the oxide inside first groove, the first drift layer 303 and the surface of the first oxide layer 307 are carried out flat Change is handled, as illustrated in figure 3h;

S309, using hot wall LPCVD techniques in the first drift layer 303 and the surface epitaxial growth thickness of the first oxide layer 307 For 1~20 μm, Nitrogen ion doping concentration is 1 × 1014~1 × 1015cm-3The second drift layer 308, wherein the second drift layer 308 Thickness be also an option that 5 μm, Nitrogen ion doping concentration is also an option that 2 × 1014cm-3, it is unified for convenience of display in figure First drift layer 303 and the second drift layer 308 are referred to as drift layer 3001, as shown in figure 3i;

S310, using hot wall LPCVD techniques, be 0.5~2 μm in the Epitaxial growth depth of drift layer 3001, aluminium ion is mixed Miscellaneous concentration 1 × 1017~1 × 1018cm-3P type trap zone 309, the depth of wherein P type trap zone 309 is also an option that 1 μm, 1.5 μm, Al-doping concentration is also an option that 3 × 1017cm-3、8×1017cm-3, as shown in Fig. 3 j;

S311, utilize ion implantation technology, the multiple selective Al ion implantation in P type trap zone 309, by injectant Amount and correspondingly energy control to form thickness as 0.1~0.5 μm, and Al-doping concentration is 1 × 1019~1 × 1021cm-3P+ Doped region 310, it is that thickness is 0.01~0.1 μm to form thickness, and Al-doping concentration is 2 × 1017~1 × 1018cm-3P connect Area 311 is touched, the wherein concentration of P contact zones 311 is less than P+ doped regions 310, as shown in figure 3k;

S312, using ion implantation technology, the multiple selective N~+ implantation in P type trap zone 309, forming depth is 0.1~0.5 μm, Nitrogen ion doping concentration 1 × 1018~1 × 1020cm-3N+ launch sites 312, wherein N+ launch sites 312 depth Degree is also an option that 0.15 μm, and Nitrogen ion doping concentration is also an option that 1 × 1019cm-3, as shown in Fig. 3 l;

S313, the oxide layer 307 of drift layer 3001 and first, preparation second groove are etched using reactive ion etching process 313, the width of second groove 313 is less than the width of first groove 306, forms buries oxide layer 314, buries oxide layer 314 is positioned at drift Move in layer 3001, the both sides of second groove 313, as shown in figure 3m;

S314, using thermal oxidation technology second groove 313 formed the second oxide layer 315, using CVD techniques, second The depositing polysilicon 316 of groove 313, as shown in figure 3n;

S315, in whole device surface (i.e. N+ launch sites 312, P contact zones 311, the second oxide layer 315 and polysilicon 316) surface deposition photoresist, the photoresist developing of the top of N+ launch sites 312 is formed into emitter stage metal ohmic contact window, Whole device surface deposit Ni/Ti/Al alloys, using ultrasonic wave stripping technology, at a temperature of 900 DEG C, anneal 5 in nitrogen atmosphere Minute, form emitter stage Ohm contact electrode 317;As shown in Fig. 3 o.

S316, in whole device surface (N+ launch sites 312, P contact zones 311, the second oxide layer 315 and polysilicon 316 On) deposit photoresist, the photoresist developing of the top of P contact zones 311 is formed into emitter stage Schottky contact metal window, whole Device surface deposits W metal, and emitter stage Schottky contact electrode 318 is formed using ultrasonic wave stripping technology;Further, send out Emitter-base bandgap grading Ohm contact electrode 317 and emitter stage Schottky contact electrode 318 may be at short circuit state;As shown in Fig. 3 p.

S317, deposit form collector contact metal level.Ti/Al alloys are deposited in the lower surface of current collection layer 305, as collection Electrode contacting metal, annealed at a temperature of 1050 DEG C, in nitrogen atmosphere 3 minutes and form colelctor electrode 319, as shown in Fig. 3 q.

Example IV

Fig. 4 is referred to, Fig. 4 injects enhanced SiC PNM- for a kind of Novel Schottky contact provided in an embodiment of the present invention The schematic diagram of p-IGBT devices.

Device architecture includes:Current collection layer 401, cushion 402, drift layer 403, N-type base 404, N+ doped regions 405, N Contact zone 406, P+ launch sites 407, buries oxide layer 408, emitter stage Ohm contact electrode 409, emitter stage Schottky contact electrode 410 and emitter contact electrode 411, wherein, the buries oxide layer 408 is located in drift layer.

Preferably, current collection layer 401 is N+ current collection layers, and cushion 402 is P+ cushions, and drift layer 403 is P- drift layers.

Embodiment five

Fig. 5 a- Fig. 5 n, Fig. 5 a- Fig. 5 n are referred to for a kind of Novel Schottky contact injection provided in an embodiment of the present invention to increase For the process schematic representation of strong type SiC PNM-p-IGBT devices on the basis of above-described embodiment, the present embodiment will be right in more detail The technological process of the present invention is introduced.This method includes:

S501, N+SiC substrates 501 are chosen, RCK standard cleanings are carried out to N+SiC substrates 501, as shown in Figure 5 a;

S502, using hot wall LPCVD techniques the epitaxial thickness of N+SiC substrates 501 be 1~10 μm, Nitrogen ion doping concentration 1 ×1016~1 × 1018cm-3Cushion 502, the thickness of wherein cushion 502 is also an option that 3 μm, Nitrogen ion doping concentration It is also an option that 1 × 1017cm-3, as shown in Figure 5 b;

S503, using hot wall LPCVD techniques, epitaxial thickness is 100~200 μm on cushion 502, and Al-doping is dense Spend for 1 × 1014~1 × 1015cm-3The first drift layer 503, wherein the thick bottom of the first drift layer 503 is also an option that 135 μ M, Al-doping concentration are also an option that 2 × 1014cm-3, as shown in Figure 5 c;

S504, using reactive ion etching process etch the first drift layer 503, formed first groove 504, depth be 1~ 10 μm, as fig 5d;

S505, using thermal oxidation technology first groove 504 deposit the first oxide layer 505, grind off on the first drift layer Oxide, only retain the oxide inside first groove, the first drift layer 503 and the surface of the first oxide layer 505 are carried out flat Change is handled, as depicted in fig. 5e;

S506, using hot wall LPCVD techniques the first drift layer 503 and the surface epitaxial thickness of the first oxide layer 505 be 1~ 20 μm, Al-doping concentration is 1 × 1014~1 × 1015cm-3The second drift layer 506, wherein the thickness of the second drift layer 506 Degree is also an option that 5 μm, and Al-doping concentration is also an option that 2 × 1014cm-3, it is unified by for convenience of showing in figure One drift layer 503 and the second drift layer 506 are referred to as drift layer 5001, as shown in figure 5f;

S507, using hot wall LPCVD techniques, be 0.5~2 μm in the Epitaxial growth depth of drift layer 5001, Nitrogen ion is mixed Miscellaneous concentration 1 × 1017~1 × 1018cm-3N-type well region 507, the depth of wherein N-type well region 507 is also an option that 1 μm, 1.5 μm, Nitrogen ion doping concentration is also an option that 3 × 1017cm-3、8×1017cm-3, as shown in fig. 5g;

S508, utilize ion implantation technology, the multiple selective N~+ implantation in N-type well region 507, by injectant Amount and correspondingly energy control to form thickness as 0.1~0.5 μm, and Nitrogen ion doping concentration is 1 × 1019~1 × 1021cm-3N+ Doped region 508, it is that thickness is 0.01~0.1 μm to form thickness, and Nitrogen ion doping concentration is 5 × 1017~1 × 1018cm-3N connect Area 509 is touched, the wherein concentration of N contact zones is less than N+ doped regions, and N contact zones surface concentration is minimum, as shown in figure 5h;

S509, using ion implantation technology, the multiple selective Al ion implantation in N-type well region 507, forming depth is 0.1~0.5 μm, Al-doping concentration is 1 × 1018~1 × 1020cm-3P+ launch sites 510, wherein P+ launch sites 510 Depth be also an option that 0.15 μm, Al-doping concentration be also an option that 1 × 1019cm-3, as shown in figure 5i;

S510, the oxide layer 505 of drift layer 5001 and first, preparation second groove are etched using reactive ion etching process 511, the width of second groove 511 is less than the width of first groove 504, forms buries oxide layer 512, buries oxide layer 512 is positioned at drift Move in layer 5001, the both sides of second groove 511, as shown in figure 5j;

S511, using thermal oxidation technology second groove 511 formed the second oxide layer 513, using CVD techniques, second The depositing polysilicon 514 of groove 511, as shown in figure 5k;

S512, in whole device surface (i.e. N contact zones 509, P+ launch sites 510, the second oxide layer 513 and polysilicon 514 surfaces) deposit Ti/Al alloys, emitter stage ohmic contact metal layer is prepared using ultrasonic wave stripping technology, in 1050 DEG C of temperature Under, annealed 3 minutes in nitrogen atmosphere, emitter stage Ohm contact electrode 515 is formed, as shown in Fig. 5 l;

S513, in whole device surface (i.e. N contact zones 509, P+ launch sites 510, the second oxide layer 513 and polysilicon 514 surfaces) deposit photoresist, the photoresist developing on N contact zones 509 is formed into emitter stage Schottky contact metal window, Whole device surface deposit W metal, forms emitter stage Schottky contact electrode 516, further using ultrasonic wave stripping technology Ground, emitter stage Ohm contact electrode 515 and emitter stage Schottky contact electrode 516 may be at short circuit state, such as Fig. 5 m institutes Show;

S514, deposit form collector contact metal level.Ti/Al alloys are deposited in the lower surface of current collection layer 501, as collection Electrode contacting metal, annealed at a temperature of 900 DEG C, in nitrogen atmosphere 5 minutes and form colelctor electrode 517, as shown in figure 5n.

In summary, specific case used herein injects enhanced SiC to the present invention based on Novel Schottky contact PNM-IGBT device its preparation methods are set forth, and the explanation of above example is only intended to help the method for understanding the present invention And its core concept;Meanwhile for those of ordinary skill in the art, according to the thought of the present invention, in embodiment and There will be changes in application, in summary, this specification content should not be construed as limiting the invention, the present invention Protection domain should be defined by appended claim.

Claims (10)

1. the preparation method of enhanced SiC PNM-IGBT devices is injected in a kind of Novel Schottky contact, it is characterised in that including:
Using hot wall LPCVD techniques transition zone, the first drift layer, cushion, current collection layer are continuously grown in SiC substrate;
First drift layer is etched using reactive ion etching process, first groove is formed, using thermal oxidation technology described The oxide layer of first groove growth regulation one;
Using hot wall LPCVD techniques in the second drift layer of first drift layer and the first oxide layer superficial growth;
Using hot wall LPCVD techniques in the second drift layer growing P-type well region;
Using ion implantation technology P+ doped regions, P contact zones and N+ launch sites are formed in the P type trap zone;
Second drift layer and first oxide layer are etched using reactive ion etching process, forms second groove to prepare Go out buries oxide layer;
Using thermal oxidation technology in the second groove growth regulation dioxide layer, given birth to using CVD techniques in second oxide layer Long polysilicon;
Deposited metal forms emitter stage Ohm contact electrode, emitter stage Schottky contact electrode and collector contact electricity respectively Pole.
2. the method as described in claim 1, it is characterised in that using thermal oxidation technology in the oxygen of first groove growth regulation one Change layer, including:
The first oxide layer described in continued propagation in the first groove, until the depth and described first of first oxide layer Drift layer is concordant;
Remove first oxide layer on first drift layer;
Planarization process is carried out to first oxide layer and first drift layer.
3. the method as described in claim 1, it is characterised in that using thermal oxidation technology in the oxygen of first groove growth regulation one Before changing layer, in addition to:
Using CMP, the SiC substrate and the transition zone are removed.
4. the method as described in claim 1, it is characterised in that the life on second drift layer using hot wall LPCVD techniques Long P type trap zone, including:
Using hot wall LPCVD techniques second drift layer growth depth be 0.5~2 μm, Al-doping concentration be 1 × 1017~1 × 1018cm-3The P type trap zone.
5. the method as described in claim 1, it is characterised in that form P+ in the P type trap zone using ion implantation technology and mix Miscellaneous area, P contact zones and N+ launch sites, including:
Using ion implantation technology the P type trap zone formed depth be 0.1~0.5 μm, Al-doping concentration be 1 × 1019 ~1 × 1021cm-3The P+ doped regions;
Using ion implantation technology the P type trap zone formed depth be 0.01~0.1 μm, Al-doping concentration be 2 × 1017 ~1 × 1018cm-3The P contact zones;
Using ion implantation technology the P type trap zone formed depth be 0.1~0.5 μm, Nitrogen ion doping concentration be 1 × 1018 ~1 × 1020cm-3The N+ launch sites.
6. the method as described in claim 1, it is characterised in that the width of the second groove is less than the width of the first groove Degree.
7. the method as described in claim 1, it is characterised in that deposited metal forms emitter stage Ohm contact electrode, including:
Photoresist is deposited in whole device surface, development forms emitter stage metal ohmic contact window, is formed sediment in whole device surface Product Ni/Ti/Al alloys, emitter stage ohmic contact metal layer is formed using ultrasonic wave stripping technology;
At a temperature of 900 DEG C, annealed 5 minutes in nitrogen atmosphere, form the emitter stage Ohm contact electrode.
8. the method as described in claim 1, it is characterised in that deposited metal forms emitter stage Schottky contact electrode, bag Include:
Photoresist is deposited in whole device surface, development forms emitter stage Schottky contact metal window, in whole device surface W metal is deposited, the emitter stage Schottky contact electrode is formed using ultrasonic wave stripping technology.
9. the method as described in claim 1, it is characterised in that deposited metal forms emitter contact electrode, including:
Ti/Al alloys are deposited in the current collection layer lower surface, form collector contact metal;
At a temperature of 1050 DEG C, annealed 3 minutes in nitrogen atmosphere and form the emitter contact electrode.
10. enhanced SiC PNM-IGBT devices are injected in a kind of Novel Schottky contact, it is characterised in that including:Current collection layer, delay Rush layer, drift layer, P type trap zone, P+ doped regions, P contact zones, N+ launch sites, buries oxide layer, emitter stage Ohm contact electrode, hair Emitter-base bandgap grading Schottky contact electrode, emitter contact electrode, wherein, the buries oxide layer is located in the drift layer, described new The enhanced SiC PNM-IGBT devices of Schottky contacts injection are prepared as the method described in any one of claim 1~9 to be formed.
CN201710466243.8A 2017-06-19 2017-06-19 Schottky contact injection enhanced SiC PNM-IGBT device and preparation method thereof CN107507861B (en)

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Publication number Priority date Publication date Assignee Title
JPH10294461A (en) * 1997-04-21 1998-11-04 Toyota Central Res & Dev Lab Inc Insulation gate type semiconductor element
CN105206656A (en) * 2015-08-25 2015-12-30 电子科技大学 Reverse conducting IGBT device
CN106409898A (en) * 2016-11-01 2017-02-15 株洲中车时代电气股份有限公司 Trench gate IGBT (Insulated Gate Bipolar Transistor) with buried oxide layers and fabrication method thereof

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JPH10294461A (en) * 1997-04-21 1998-11-04 Toyota Central Res & Dev Lab Inc Insulation gate type semiconductor element
CN105206656A (en) * 2015-08-25 2015-12-30 电子科技大学 Reverse conducting IGBT device
CN106409898A (en) * 2016-11-01 2017-02-15 株洲中车时代电气股份有限公司 Trench gate IGBT (Insulated Gate Bipolar Transistor) with buried oxide layers and fabrication method thereof

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