CN207068861U - Knot terminal terminal extension structure - Google Patents
Knot terminal terminal extension structure Download PDFInfo
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- CN207068861U CN207068861U CN201721069330.1U CN201721069330U CN207068861U CN 207068861 U CN207068861 U CN 207068861U CN 201721069330 U CN201721069330 U CN 201721069330U CN 207068861 U CN207068861 U CN 207068861U
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Abstract
A kind of knot terminal terminal extension structure is the utility model is related to, the structure includes：SiC substrate layer 201；Epitaxial layer 202, it is arranged at the surface of SiC substrate layer 201；Knot terminal expansion area 203, it is arranged in the epitaxial layer 202；Active area 205, it is arranged at the side of knot terminal expansion area 203 and in the epitaxial layer 202；Passivation layer 204, it is arranged at the surface of epitaxial layer 202.Terminal structure of the present utility model eliminates the sharp electric field peak of single-point of conventional junction termination extension edge by the edge charges distribution of linear change, alleviate the electric field concentration effect at knot edge, so as to reduce device because single-point high electric field induces the extra risk leaked electricity and punctured in advance, improve reliability of the knot terminal expansion structure when reversely pressure-resistant.
Description
Technical field
Technical field of semiconductor device is the utility model is related to, more particularly to a kind of knot terminal terminal extension structure.
Background technology
With the fast development of Power Electronic Technique, traditional silicon (Si) base power device just fast approaching its material from
The theoretical limit that body characteristic is determined is simple to enter one by the design, technique, integration of optimization Si base devices and its circuit module
Step excavate its performance potential, can not meet current Power Electronic Technique high efficiency, low energy consumption it is inherently required.Meanwhile by
In the development of the technologies such as military integrated electronic system, Aero-Space, high-speed rail transportation, intelligent grid, power is not required nothing more than
Device can form the Solid State Electronics circuit of more power density, and need power device can be in high temperature, intense radiation etc.
Extreme environment works, and this is even more traditional Si material and the impassable technology barriers of device.Third generation ARTSemiconductor silicon carbide
(SiC) there is broad stopband (3 times of Si), high critical breakdown electric field (8~10 times of Si), high heat conductance (3 times of Si),
It is to prepare high-power, high temperature, the most important semi-conducting material of radioresistance power electronic devices.Broad stopband characteristic is advantageous to improve device
The operating temperature and capability of resistance to radiation of part；High critical breakdown electric field characteristic is advantageous to improve the overvoltage capacity of device；High heat conductance
Characteristic is advantageous to heat dissipation and High Density Integration of device etc..As can be seen here, power electronic system can be made using SiC base devices
The ability such as power, efficiency, temperature and radioresistance be significantly improved.
Recently as the continuous maturation of SiC single crystal, epitaxial material and processing technology, SiC power devices enter system
Comprehensive conceptual phase.In order to improve the pressure-resistant reliability of reality of the device under reverse-biased working condition, alleviate P-N junction edge due to
Inherent curvature effect and the electric field concentration phenomenon occurred, terminal structure are widely used.Wherein, knot terminal extension knot
Structure is widely adopted with its higher end use efficiency, the easily designed and advantage such as preparation.Its essence is by knot termination environment
The completely depleted of portion's electric charge balances the peak value electric field of inside and outside two edges, and it is critical two electric field values is reached SiC together
Breakdown electric field is optimal.
But the thermal diffusion coefficient very little due to impurity in SiC material, diffusion technique can not carry out selective doping,
Therefore SiC knot terminal expansion structure can only rely on ion implantation technology to realize, and equally pass through high temperature without image of Buddha Si materials
Knot technique forms preferable cylinder or the sphere knot of larger radius of curvature in injection area edge.This has resulted in the extension of SiC knot terminals
The knot edge approximation of structure maintains " sharp " the injection edge pattern of small radius of curvature.The knot edge geometrical morphology of " sharp " will
SiC device is caused to form intrinsic body and the sharp electric field peak of surface single-point under reverse bias particularly high-V alloy state, and then
Induce extra electric leakage, even puncture in advance, so as to reduce the pressure-resistant reliability of device.
Utility model content
Therefore, to solve technological deficiency and deficiency existing for prior art, the utility model proposes a kind of extension of knot terminal
Terminal structure.
Specifically, a kind of knot terminal terminal extension structure that the utility model one embodiment proposes, including：
SiC substrate layer 201；
Epitaxial layer 202, it is arranged at the surface of SiC substrate layer 201；
Knot terminal expansion area 203, it is arranged in the epitaxial layer 202；
Active area 205, it is arranged at the outside of knot terminal expansion area 203 and in the epitaxial layer 202；
Passivation layer 204, it is arranged at the epi-layer surface 207.
In one embodiment of the present utility model, the epitaxial layer 202 is N-type SiC.
In one embodiment of the present utility model, the knot terminal expansion area 203 is p-type SiC.
In one embodiment of the present utility model, the knot terminal expansion area 203 includes horizontal junction depth transition region and the
One doping junction depth contour line 206A, wherein,
The horizontal junction depth transition region is arranged at the edge of the knot terminal expansion area 203；
The first doping junction depth contour line 206A is located at the triangle hypotenuse of the horizontal junction depth transition region.
In one embodiment of the present utility model, the first doping junction depth contour line 206A and the epi-layer surface
207 angle is 5 °~20 °.
In one embodiment of the present utility model, the width of the knot terminal expansion area 203 is 40 μm~600 μm, deep
Spend for 0.6 μm~1.2 μm.
In one embodiment of the present utility model, the knot terminal expansion area 203 extends including first step knot terminal
Area and second step knot terminal expansion area.
In one embodiment of the present utility model, the width of the first step knot terminal expansion area is 20 μm~300 μ
M, depth is 0.8 μm~1.2 μm, the second doping junction depth contour line 206B of the first step knot terminal expansion area with it is described outer
The angle for prolonging layer surface 207 is 5~15 °.
In one embodiment of the present utility model, the width of the second step knot terminal expansion area is 20 μm~300 μ
M, depth is 0.4 μm~0.6 μm, the 3rd doping junction depth contour line 206C of the second step knot terminal expansion area with it is described outer
The angle for prolonging layer surface 207 is 5~15 °.
In one embodiment of the present utility model, the depth of the active area 205 is 0.5 μm~1 μm.
Compared with prior art, the beneficial effects of the utility model are,
1st, structure is enclosed by doping junction depth contour line and epi-layer surface by being introduced at the edge of conventional junction termination extension structure
The micron order transverse direction junction depth gradual change trigonum formed, a continuous, grade doping area for linear change is constructed, changes tradition
P-N junction edge pattern in carborundum knot terminal expansion structure, avoid the Macroscopic Curvature effect at " sharp " knot edge.
2nd, the single-point cutting edge of a knife or a sword of Conventional silicon carbide knot terminal extension edge is eliminated by the edge charges distribution of linear change
Sharp electric field peak simultaneously reduces peak value electric field value, alleviates the electric field concentration effect for finishing edge, so as to reduce device due to the high electricity of single-point
The extra risk leaked electricity and punctured in advance is induced, improve reliability of the knot terminal expansion structure when reversely pressure-resistant.
By the detailed description below with reference to accompanying drawing, other side and feature of the present utility model become obvious.But should
When knowing, the accompanying drawing is only the purpose design explained, not as the restriction of the scope of the utility model, because its
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 are only
Try hard to conceptually illustrate structure and flow described herein.
Brief description of the drawings
Below in conjunction with accompanying drawing, specific embodiment of the present utility model is described in detail.
Fig. 1 a are a kind of knot terminal terminal extension structural profile illustration that the utility model embodiment provides；
Fig. 1 b are another knot terminal terminal extension structural profile illustration that the utility model embodiment provides；
Fig. 2 a~Fig. 2 k are that a kind of technological process for knot terminal terminal extension structure that the utility model embodiment provides is shown
It is intended to；
Fig. 3 a are the knot terminal terminal extension structure that a kind of edge inclination angle that the utility model embodiment provides is 5 ° and showed
There is the knot terminal terminal extension structural profile illustration that edge inclination angle is 80 ° in technology；
Fig. 3 b~Fig. 3 c be the utility model embodiment provide a kind of knot terminal terminal extension structure with the prior art
The electricity numerical simulation comparing result schematic diagram of typical knot terminal terminal extension structure；
Fig. 4 is another knot terminal terminal extension structural profile illustration that the utility model embodiment provides；
Fig. 5 a~Fig. 5 f are the technological process for another knot terminal terminal extension structure that the utility model embodiment provides
Schematic diagram.
Embodiment
To enable above-mentioned purpose of the present utility model, feature and advantage more obvious understandable, below in conjunction with the accompanying drawings to this
The embodiment of utility model is described in detail.
Embodiment one
Fig. 1 a are referred to, Fig. 1 a are a kind of knot terminal terminal extension structural profile signal that the utility model embodiment provides
Figure.The structure includes：
SiC substrate layer 201；
Epitaxial layer 202, it is arranged at the surface of SiC substrate layer 201；
Knot terminal expansion area 203, it is arranged in the epitaxial layer 202；
Active area 205, it is arranged at the outside of knot terminal expansion area 203 and in the epitaxial layer 202；
Passivation layer 204, it is arranged at the epi-layer surface 207.
Further, the epitaxial layer 202 is N-type SiC.
Further, the knot terminal expansion area 203 is p-type SiC.
Further, the knot terminal expansion area 203 includes horizontal junction depth transition region and the first doping junction depth contour line
206A, wherein,
The horizontal junction depth transition region is arranged at the edge of the knot terminal expansion area 203；
The first doping junction depth contour line 206A is located at the triangle hypotenuse of the horizontal junction depth transition region.
Further, the angle of the first doping junction depth contour line 206A and the epi-layer surface 207 be 5 °~
20°。
Further, the width of the knot terminal expansion area 203 is 40 μm~600 μm, and depth is 0.6 μm~1.2 μm.
Further, the knot terminal expansion area 203 includes first step knot terminal expansion area and second step knot is whole
Hold expansion area.
Further, the width of the first step knot terminal expansion area be 20 μm~300 μm, depth be 0.8 μm~1.2
μm, the second doping junction depth contour line 206B and the angle of the epi-layer surface 207 of the first step knot terminal expansion area
For 5~15 °.
Further, the width of the second step knot terminal expansion area be 20 μm~300 μm, depth be 0.4 μm~0.6
μm, the 3rd doping junction depth contour line 206C and the angle of the epi-layer surface 207 of the second step knot terminal expansion area
For 5~15 °.
Further, the depth of the active area 205 is 0.5 μm~1 μm.
Present embodiments provide the example that p-type knot terminal expansion area is made in N-type epitaxy layer, those skilled in the art
Can easily it deduce, the structure can equally make N type junction termination extension area on p-type epitaxial layer, only need to convert this reality
Apply corresponding conduction type in example.
The beneficial effects of the utility model are specially：
1. structure is enclosed by doping junction depth contour line and epi-layer surface by being introduced at the edge of conventional junction termination extension structure
The micron order transverse direction junction depth gradual change trigonum formed, can be with structure using knot terminal terminal extension structure provided by the utility model
A continuous, grade doping area for linear change is produced, changes the P-N junction edge in Conventional silicon carbide knot terminal expansion structure
Pattern, avoid the Macroscopic Curvature effect at " sharp " knot edge；
2. the single-point cutting edge of a knife or a sword of Conventional silicon carbide knot terminal extension edge is eliminated by the edge charges distribution of linear change
Sharp electric field peak simultaneously reduces peak value electric field value, alleviates the electric field concentration effect for finishing edge, so as to reduce device due to the high electricity of single-point
The extra risk leaked electricity and punctured in advance is induced, improve reliability of the knot terminal expansion structure when reversely pressure-resistant.
Embodiment two
Refer to the technique that Fig. 2 a~Fig. 2 k are a kind of knot terminal terminal extension structure that the utility model embodiment provides
Schematic flow sheet.On the basis of above-described embodiment, the present embodiment will enter to technological process of the present utility model in more detail
Row is introduced.This method includes：
S1, substrate are chosen.It is 5 × 10 to choose doping concentration18cm-3, N-type SiC substrate layer 101 that thickness is 350 μm be just
Beginning material.
S2, outer layer growth.As shown in Figure 2 a, adulterated using epitaxial growth method in the superficial growth of SiC substrate layer 101
Concentration is 1 × 1014cm-3~1 × 1016cm-3rd, thickness is 5~200 μm of lightly doped n type SiC epitaxial layer 102, the epitaxial layer
102 have the first conduction type；
Preferably, the doping concentration of the epitaxial layer 102 is 1 × 1014cm-3、5×1014cm-3、1×1015cm-3With 5 ×
1015cm-3；
Preferably, the thickness of the epitaxial layer 102 is 10 μm, 30 μm, 100 μm and 150 μm.
S3, the first mask layer preparation.As shown in Figure 2 a：
S301, using pecvd process the first SiO is deposited in the epi-layer surface 1052Layer 108；
S302, rapid thermal annealing is carried out at a temperature of 800~1100 DEG C, annealing time is 2~30min；
S303, using pecvd process in the first SiO2Layer deposits the 2nd SiO on 108 surface2Layer 109, by first
SiO2The SiO of layer 108 and the 2nd2Layer 109 forms the first mask layer that gross thickness is 2 μm.
S4, the first ion implantation mask layer preparation.As shown in Fig. 2 b and Fig. 2 c：
S401, in the 2nd SiO2The first photoresist layer of surface spin coating 110 of layer 109, through graphical exposure, development and to protecting
The first photoresist layer 110 stayed carries out ultra-violet curing processing, forms the first etching window of the first mask layer；
S402, using buffered oxide etch liquid (Buffered oxide etching, abbreviation BOE) to the first mask layer
Wet etching perforate is carried out, forms the first ion implantation mask layer.
In this step, compared to the first SiO by annealing densified2Layer 108, directly deposit, without by moving back
2nd SiO of fire processing2Layer 109 is more easy to be corroded because quality is more loose, and this lateral encroaching speed difference will change SiO2
Isotropic wet etching characteristic so that BOE is to double-deck SiO2Mask layer is particularly the first SiO2The corrosion on 108 top of layer is more
To be effective, the perforate pattern with small angle inclination edge is as a result formed.By adjusting the first SiO2The annealing bar of layer 108
Part and upper and lower two layers of SiO2Thickness proportion, with control inject mask edge tilt angle.
S5, the preparation of knot terminal expansion area.As shown in Figure 2 d：
S501, the first photoresist layer 110 is removed, using ion implantation technology in the first ion implantation mask layer and described outer
Prolong layer surface 105 and carry out ion implanting, by means of the SiO at small angle inclination edge2First ion implantation mask layer, described outer
Prolong and the knot terminal expansion area 103 with the second conduction type is formed in layer 102, the lateral junction in the knot terminal expansion area 103
Deep transition region is located at the edge of knot terminal expansion area 103 and distribution triangular in shape.The first doping knot at horizontal junction depth transition region edge
Angle angle between deep contour line 104 and epi-layer surface 105 is 5 °~20 °, the as side of the first ion implantation mask layer
Edge angle of inclination.The first ion implantation mask layer within edge will stop that injection ion enters epitaxial layer 102.The knot terminal
The material of expansion area 103 is p-type SiC, and doping concentration is 0.8 × 1017cm-3~2 × 1017cm-3, width is 40 μm~600 μm,
Depth is 0.6 μm~1.2 μm；
S502, the first ion implantation mask layer is washed, form mating plate, as shown in Figure 2 e；
Preferably, the angle angle between the first doping junction depth contour line 104 and epi-layer surface 105 be 5 °,
12°、15°、20°；
Preferably, the doping concentration of the knot terminal expansion area 103 is 1 × 1017cm-3、1.3×1017cm-3、1.5×
1017cm-3With 1.8 × 1017cm-3；
Preferably, the width of the knot terminal expansion area 103 is 40 μm, 120 μm, 400 μm and 600 μm；
Preferably, the depth of the knot terminal expansion area 103 is 0.7 μm, 0.8 μm, 1 μm and 1.2 μm.
S6, the second mask layer preparation.The SiO that PECVD deposition thickness is 2 μm is re-used in epi-layer surface 1052
Form the second mask layer 111.
S7, the second ion implantation mask layer preparation.As shown in Fig. 2 f and 2g：
S701, the second photoresist layer of surface spin coating 112 in the second mask layer 111, through graphical exposure, development and to protecting
The second photoresist layer 112 stayed carries out ultra-violet curing processing, forms the second etching window of the second mask layer 111；
S702, using inductively coupled plasma etching (nductively coupled plasma etching, referred to as
ICP dry etching perforate) is carried out to the second mask layer 111, forms the second ion implantation mask layer.In this step, by excellent
Change plasma etch process parameter, to control the verge of opening pattern of mask layer, form the SiO near normal edge2
Second ion implantation mask layer.
S8, active area preparation, as shown in fig. 2h.
S801, remove the second photoresist layer 112；
S802, using ion implantation technology ion is injected in the second ion implantation mask layer and epi-layer surface 105, tied
The side in termination extension area 103 forms the active area 107 with the second conduction type, and active area 107 is located at the epitaxial layer 102
Interior, the second ion implantation mask layer will stop that injection ion enters epitaxial layer 102 completely.
S803, the second ion implantation mask layer is washed, form mating plate, as shown in fig. 2i.
S9, the activation for injecting ion.As shown in figure 2j, carbon film is formed by magnetically controlled sputter method in epi-layer surface 105
113, line activating is entered to injection ion by high annealing, the temperature of high annealing is 1600~1800 DEG C, annealing time 10~
60min；
S10, insulating passivation layer preparation, as shown in Fig. 2 k.Carbon film 113 is removed, is formed above knot terminal expansion area 103
Insulating passivation layer 106, form the knot terminal terminal extension structure with laterally graded junction depth marginal zone.
Embodiment three
Fig. 1 a are referred to, Fig. 1 a are a kind of knot terminal terminal extension structural profile signal that the utility model embodiment provides
Figure.The knot terminal terminal extension structure includes：
SiC substrate layer 201；
Wherein, SiC substrate layer 201 is 5 × 10 by doping concentration18cm-3N-type SiC material form, thickness be 350 μm.
Epitaxial layer 202, it is formed on SiC substrate layer 201；
Wherein, epitaxial layer 202 is made up of lightly doped n type SiC material, has the first conduction type, and doping concentration is 1 ×
1014cm-3~1 × 1016cm-3, thickness is 5~200 μm.
Knot terminal expansion area 203, it is arranged in epitaxial layer 202；
Wherein, knot terminal expansion area 203 is made up of p-type SiC material, has the second conduction type, and doping concentration is 0.8 ×
1017cm-3~2 × 1017cm-3, width is 40 μm~600 μm, and depth is 0.6 μm~1.2 μm.
Horizontal junction depth transition region, the edge of knot terminal expansion area 203 is arranged at, there is angle of collimation delta-shaped region shape
Looks；
Wherein, first doping junction depth contour line 206A and the epi-layer surface 207 at the horizontal junction depth transition region edge it
Between angle be 5~20 °.
Passivation layer 204, it is covered in the top of knot terminal expansion area 203；
Wherein, the thickness of passivation layer 204 is 0.5 μm~2.5 μm.
Active area 205, it is arranged in epitaxial layer 202；
Wherein, active area 205 has the second conduction type, and depth is 0.5 μm~1 μm, and adjacent with knot terminal expansion area 203
Connect, contacted with the part of passivation layer 204.
Example IV
Referring again to Fig. 1 a, the present embodiment, which provides another knot terminal terminal extension structure, to be included：
SiC substrate layer 201；
Wherein, SiC substrate layer 201 is 5 × 10 by doping concentration18cm-3N-type SiC material form, thickness be 350 μm.
Epitaxial layer 202, it is formed on SiC substrate layer 201；
Wherein, epitaxial layer 202 is made up of lightly doped n type SiC material, has the first conduction type, and doping concentration is 5 ×
1015cm-3, thickness is 10 μm.
Knot terminal expansion area 203, it is arranged in epitaxial layer 202；
Wherein, knot terminal expansion area 203 is made up of p-type SiC material, has the second conduction type, and doping concentration is 1.8 ×
1017cm-3, width is 40 μm, and depth is 0.7 μm.
Horizontal junction depth transition region, the edge of knot terminal expansion area 203 is arranged at, there is angle of collimation delta-shaped region shape
Looks；
Wherein, first doping junction depth contour line 206A and the epi-layer surface 207 at the horizontal junction depth transition region edge it
Between angle be 20 °.
Passivation layer 204, it is covered in the top of knot terminal expansion area 203；
Wherein, the thickness of passivation layer 204 is 1 μm.
Active area 205, it is arranged in epitaxial layer 202；
Wherein, active area 205 has the second conduction type, and depth is 0.7 μm, and abutted with knot terminal expansion area 203, with
The part of passivation layer 204 contacts.
Embodiment five
Referring again to Fig. 1 a, the present embodiment, which provides another knot terminal terminal extension structure, to be included：
SiC substrate layer 201；
Wherein, SiC substrate layer 201 is 5 × 10 by doping concentration18cm-3N-type SiC material form, thickness be 350 μm；
Epitaxial layer 202, it is formed on SiC substrate layer 201；
Wherein, epitaxial layer 202 is made up of lightly doped n type SiC material, has the first conduction type, and doping concentration 1 ×
1015cm-3, thickness is 30 μm.
Knot terminal expansion area 203, it is arranged in epitaxial layer 202；
Wherein, knot terminal expansion area 203 is made up of p-type SiC material, has the second conduction type, and doping concentration is 1.3 ×
1017cm-3, width is 120 μm, and depth is 0.8 μm.
Horizontal junction depth transition region, the edge of knot terminal expansion area 203 is arranged at, there is angle of collimation delta-shaped region shape
Looks；
Wherein, first doping junction depth contour line 206A and the epi-layer surface 207 at the horizontal junction depth transition region edge it
Between angle be 12 °.
Passivation layer 204, it is covered in the top of knot terminal expansion area 203；
Wherein, the thickness of passivation layer 204 is 1.5 μm；
Active area 205, it is arranged in epitaxial layer 202；
Wherein, active area 205 has the second conduction type, and depth is 0.8 μm, and abutted with knot terminal expansion area 203, with
The part of passivation layer 204 contacts.
Embodiment six
Fig. 4 is referred to, Fig. 4 is another knot terminal terminal extension structural profile signal that the utility model embodiment provides
Figure.The termination extension terminal structure includes：
SiC substrate layer 201；
Wherein, SiC substrate layer 201 is 5 × 10 by doping concentration18cm-3N-type SiC material form, thickness be 350 μm；
Epitaxial layer 202, it is formed on SiC substrate layer 201；
Wherein, epitaxial layer 202 is made up of lightly doped n type SiC material, has the first conduction type, and doping concentration is 5 ×
1014cm-3, thickness is 100 μm；
Knot terminal expansion area 203, it is arranged in epitaxial layer 202；
Wherein, knot terminal expansion area 203 is made up of p-type SiC material, has the second conduction type, and doping concentration 1 ×
1017cm-3, 400 μm of width, 1 μm of depth；
Horizontal junction depth transition region, the edge of knot terminal expansion area 203 is arranged at, there is angle of collimation delta-shaped region pattern；
Wherein, first doping junction depth contour line 206A and the epi-layer surface 207 at the horizontal junction depth transition region edge it
Between angle be 5 °.
Passivation layer 204, it is covered in the top of knot terminal expansion area 203；
Wherein, the thickness of passivation layer 204 is 2 μm；
Active area 205, it is arranged in epitaxial layer 202；
Wherein, active area 205 has the second conduction type, 0.7 μm of depth, and abutted with knot terminal expansion area 203, with it is blunt
Change the contact of the part of layer 204.
Refer to Fig. 3 a~Fig. 3 c, Fig. 3 a be the utility model embodiment provide a kind of edge inclination angle be 5 ° knot terminal
Terminal extension structure and in the prior art edge inclination angle are 80 ° of knot terminal terminal extension structural profile illustration；Fig. 3 b and figure
3c is that a kind of knot terminal terminal extension structure that the utility model embodiment provides extends with typical knot terminal in the prior art
The electricity numerical simulation comparing result schematic diagram of terminal structure.
Wherein, Fig. 3 a are the knot with laterally graded junction depth marginal zone prepared in emulation using the utility model embodiment
Termination extension terminal structure, knot terminal terminal extension edge inclination angle are 5 °, and Fig. 3 b and 3c give to be inclined using two kinds of different edges
The electricity Numerical Simulation Results of the knot terminal terminal extension structure at angle, two kinds of knot terminal terminal extension structures are respectively：Fig. 3 a institutes
The knot terminal terminal extension structure with laterally graded junction depth marginal zone shown and in the prior art non-vertical profile edge
SiO2The typical knot terminal terminal extension structure that the terminal edge inclination angle that injection mask is formed is 80 °.
As shown in Figure 3 b, the knot terminal with laterally graded junction depth marginal zone to be provided using the utility model embodiment
Terminal extension structure and the surface electric field distribution contrast at the terminal edge in reverse breakdown of existing knot terminal expansion structure.Can be with
Find out, the presence of laterally graded junction depth marginal zone effectively eliminates the sharp electric field of single-point of conventional junction termination extension edge
Peak, make fringe field distribution more gentle；Peak value electric field value intensity drops to 1.8MV/cm, fall by 2.6MV/cm simultaneously
Reach 30%, the Electric Field Distribution of this optimization will be effectively reduced high electric field and induce the extra risk leaked electricity and punctured in advance, carry
High knot terminal terminal extension reversely it is pressure-resistant when reliability.As shown in Figure 3 c, for using the utility model embodiment offer
Knot terminal terminal extension structure and the reverse I-V characteristic pair of existing knot terminal terminal extension with laterally graded junction depth marginal zone
Than.As can be seen that the presence of laterally graded junction depth marginal zone causes the breakdown voltage of device to effectively improve, this is equally and line
Property change the Electric Field Distribution optimization that brings of edge charges distribution it is related.
Embodiment seven
It is that another knot terminal extension that the utility model embodiment provides is whole to refer to Fig. 5 a~Fig. 5 f, Fig. 5 a~Fig. 5 f
The process flow diagram of end structure.The present embodiment will be whole to the step knot with different junction depths on the basis of embodiment two
The preparation method of end terminal extension structure is introduced, and the preparation method comprises the following steps：
S1, substrate are chosen.It is 5 × 10 to choose doping concentration18cm-3, N-type SiC substrate layer 301 that thickness is 350 μm be just
Beginning material.
S2, outer layer growth.It is described using epitaxial growth method in the superficial growth epitaxial layer 302 of SiC substrate layer 301
Epitaxial layer 302 has the first conduction type；
S3, the first ion implantation mask layer preparation, as shown in Fig. 5 a~5d.
Prepared by S31, the first mask layer of the first ion implantation mask layer, for defining the entirety of knot terminal expansion area 303
Region.
S301, using pecvd process the first SiO is deposited in the epi-layer surface 3052Layer 314；
S302, rapid thermal annealing is carried out at a temperature of 800~1100 DEG C, annealing time is 2~30min；
S303, using pecvd process in the first SiO2Layer deposits the 2nd SiO on 314 surface2Layer 315, the first SiO2
The SiO of layer 314 and the 2nd2315 gross thickness of layer are 2 μm.
S304, in the 2nd SiO2The photoresist layer of surface spin coating first of layer 315, through graphical exposure, development and to retaining
The first photoresist layer to get off carries out ultra-violet curing processing, forms the first etching window of the first mask layer；
S305, wet etching perforate, formation the first ion note are carried out to the first mask layer using buffered oxide etch liquid
Enter the first mask layer of mask layer.
Preferably, by the first SiO2The SiO of layer 314 and the 2nd2The bore size of first mask layer of the composition of layer 315 and knot are whole
Hold the overall width of expansion area 303 equal.
Prepared by S32, the second mask layer of the first ion implantation mask layer, for defining two of knot terminal expansion area 303
Step.
S306, as shown in Figure 5 b, the 3rd SiO is deposited using pecvd process in the epi-layer surface 3052Layer 316；
S307, rapid thermal annealing is carried out at a temperature of 800~1100 DEG C, annealing time is 2~30min；
S308, using pecvd process in the 3rd SiO2Layer deposits the 4th SiO on 316 surface2Layer 317, the 3rd SiO2
The SiO of layer 316 and the 4th2317 gross thickness of layer are 0.6 μm.
S309, as shown in Figure 5 c, in the 4th SiO2The first photoresist layer of surface spin coating 318 of layer 317, exposed through graphical
Light, development and the first photoresist layer 318 to remaining carry out ultra-violet curing processing, form the first etching of the first mask layer
Window；
S310, as fig 5d, wet etching perforate is carried out to the second mask layer using buffered oxide etch liquid, formed
First ion implantation mask layer.Ultimately form the first ion implantation mask layer.The verge of opening of second mask layer corresponds to knot terminal
Link position between the step of expansion area 303 two.
S4, the preparation of knot terminal expansion area.As depicted in fig. 5e：
S401, remove the first photoresist layer 318, using ion implantation technology the first ion implantation mask layer inject from
Son, the part for injecting ion is stopped using the first mask layer, forms the step knot terminal expansion area with different junction depths
303, the knot terminal expansion area 303 includes first step knot terminal expansion area and second step knot terminal expansion area；
S402, the first ion implantation mask layer is washed, form mating plate.
S5, the second mask layer preparation.PECVD deposit SiO is re-used in epi-layer surface 3052Second is formed to cover
Film layer.
S6, the second ion implantation mask layer preparation.
S601, the photoresist layer of surface spin coating second in the second mask layer, through graphical exposure, development and to remaining
The second photoresist layer carry out ultra-violet curing processing, formed the 3rd mask layer the 3rd etching window；
S602, using inductively coupled plasma etching to the 3rd mask layer carry out dry etching perforate, formed second from
Sub- injection masking layer.
S7, active area preparation.
S701, remove the second photoresist layer；
S702, using ion implantation technology the second ion implantation mask layer inject ion, in knot terminal expansion area 303
Outside forms the active area 307 with the second conduction type, and active area 307 is located in the epitaxial layer 302, the second ion implanting
Mask layer will stop that injection ion enters epitaxial layer 302 completely；
S703, the second ion implantation mask layer is washed, form mating plate.
S8, the activation for injecting ion.Carbon film 113 is formed by magnetically controlled sputter method in epi-layer surface 305, passes through high temperature
Line activating is entered in annealing to injection ion, and the temperature of high annealing is 1600~1800 DEG C, 10~60min of annealing time；
S9, insulating passivation layer 306 preparation.As shown in figure 5f, carbon film is removed, is formed above knot terminal expansion area 303
Insulating passivation layer 306, ultimately form the two step knot terminal terminal extension structures with laterally graded junction depth marginal zone.
According to the present embodiment method, can prepare to form three steps with edge transverse direction junction depth transition region, four step knots
Termination extension structure, it should not be construed as the multi-step formula knot terminal expansion structure prepared using the utility model preparation method
New utility model is created.
Embodiment eight
Fig. 1 b are referred to, Fig. 1 b are that another knot terminal terminal extension structural profile that the utility model embodiment provides shows
It is intended to, including：
SiC substrate layer 201；
Wherein, SiC substrate layer 201 is 5 × 10 by doping concentration18cm-3N-type SiC material form, thickness be 350 μm；
Epitaxial layer 202, it is formed on SiC substrate layer 201；
Wherein, epitaxial layer 202 is made up of lightly doped n type SiC material, has the first conduction type, and doping concentration is 1 ×
1014cm-3, thickness is 150 μm；
Knot terminal expansion area 203, it is arranged in epitaxial layer 202；
Wherein, knot terminal expansion area 203 is made up of p-type SiC material, has the second conduction type, and doping concentration is 1.5 ×
1017cm-3, width is 600 μm.Knot terminal expansion area 203 by junction depth not wait first step knot terminal expansion area and second
Rank knot terminal expansion area is formed, and first step knot terminal expansion area and second step knot terminal expansion area are in stepped profile.Wherein,
First knot terminal expansion area maximum junction depth depth is 1.2 μm, and minimum junction depth depth is 0.8 μm, and the second knot terminal expansion area is maximum
Junction depth depth is 0.6 μm, and minimum junction depth depth is 0.4 μm, and first step knot terminal expansion area extends with second step knot terminal
Area's stepped area width is equal, and width is 20 μm.
Horizontal junction depth transition region, it is arranged at first step knot terminal extension area edge and second step knot terminal expansion area side
Edge, there is angle of collimation delta-shaped region pattern；
Wherein, it is arranged at the second doping junction depth profile of the horizontal junction depth transition region of first step knot terminal extension area edge
Line 206B and be 5 ° parallel to the angle between the shallow step extended line 208 on the surface of epitaxial layer 202；It is arranged at second step knot end
Angle between the 3rd doping junction depth contour line 206C and epi-layer surface 207 of the horizontal junction depth transition region of end extension area edge
For 15 °.
Passivation layer 204, it is covered in the top of knot terminal expansion area 203；
Wherein, the thickness of passivation layer 204 is 2 μm.
Active area 205, it is arranged in epitaxial layer 202；
Wherein, active area 205 has the second conduction type, and depth is 0.8 μm, and abutted with knot terminal expansion area 203, with
The part of passivation layer 204 contacts.
Embodiment nine
Referring again to Fig. 1 b, Fig. 1 b are that another knot terminal terminal extension structure that the utility model embodiment provides is cutd open
Face schematic diagram, including：
SiC substrate layer 201；
Wherein, SiC substrate layer 201 is 5 × 10 by doping concentration18cm-3N-type SiC material form, thickness be 350 μm；
Epitaxial layer 202, it is formed on SiC substrate layer 201；
Wherein, epitaxial layer 202 is made up of lightly doped n type SiC material, has the first conduction type, and doping concentration is 1 ×
1014cm-3, thickness is 150 μm；
Knot terminal expansion area 203, it is arranged in epitaxial layer 202；
Wherein, knot terminal expansion area 203 is made up of p-type SiC material, has the second conduction type, and doping concentration is 1.5 ×
1017cm-3, width is 600 μm.Knot terminal expansion area 203 by junction depth not wait first step knot terminal expansion area and second
Rank knot terminal expansion area is formed, and first step knot terminal expansion area and second step knot terminal expansion area are in stepped profile.Wherein,
First knot terminal expansion area maximum junction depth depth is 1.2 μm, and minimum junction depth depth is 0.8 μm, and the second knot terminal expansion area is maximum
Junction depth depth is 0.6 μm, and minimum junction depth depth is 0.4 μm, and first step knot terminal expansion area extends with second step knot terminal
Area's stepped area width is equal, and width is 300 μm.
Horizontal junction depth transition region, it is arranged at first step knot terminal extension area edge and second step knot terminal expansion area side
Edge, there is angle of collimation delta-shaped region pattern；
Wherein, it is arranged at the second doping junction depth profile of the horizontal junction depth transition region of first step knot terminal extension area edge
Line 206B and be 15 ° parallel to the angle between the shallow step extended line 208 on the surface of epitaxial layer 202；It is arranged at second step knot
Folder between the 3rd doping junction depth contour line 206C and epi-layer surface 207 of the horizontal junction depth transition region of termination extension area edge
Angle is 5 °.
Passivation layer 204, it is covered in the top of knot terminal expansion area 203；
Wherein, the thickness of passivation layer 204 is 2 μm.
Active area 205, it is arranged in epitaxial layer 202；
Wherein, active area 205 has the second conduction type, and depth is 0.8 μm, and abutted with knot terminal expansion area 203, with
The part of passivation layer 204 contacts.
In summary, a kind of knot terminal extension that specific case used herein is provided the utility model embodiment is eventually
The principle and embodiment of end structure are set forth, the explanation of above example be only intended to help understand it is of the present utility model
Method and its core concept；Meanwhile for those of ordinary skill in the art, according to thought of the present utility model, specific real
There will be changes in mode and application are applied, in summary, this specification content should not be construed as to the utility model
Limitation, the scope of protection of the utility model should be defined by appended claim.
Claims (10)
- A kind of 1. knot terminal terminal extension structure, it is characterised in that including：SiC substrate layer (201)；Epitaxial layer (202), it is arranged at SiC substrate layer (201) surface；Knot terminal expansion area (203), it is arranged in the epitaxial layer (202)；Active area (205), it is arranged on the outside of the knot terminal expansion area (203) and in the epitaxial layer (202)；Passivation layer (204), it is arranged at the epi-layer surface (207).
- 2. structure according to claim 1, it is characterised in that the epitaxial layer (202) is N-type SiC.
- 3. structure according to claim 1, it is characterised in that the knot terminal expansion area (203) is p-type SiC.
- 4. structure according to claim 1, it is characterised in that the knot terminal expansion area (203) includes horizontal junction depth gradually Become area and the first doping junction depth contour line (206A), wherein,The horizontal junction depth transition region is arranged at the edge of the knot terminal expansion area (203)；The first doping junction depth contour line (206A) is located at the triangle hypotenuse of the horizontal junction depth transition region.
- 5. structure according to claim 4, it is characterised in that the first doping junction depth contour line (206A) with it is described outer The angle for prolonging layer surface (207) is 5 °~20 °.
- 6. structure according to claim 1, it is characterised in that the width of the knot terminal expansion area (203) be 40 μm~ 600 μm, depth is 0.6 μm~1.2 μm.
- 7. structure according to claim 1, it is characterised in that the knot terminal expansion area (203) includes first step knot Termination extension area and second step knot terminal expansion area.
- 8. structure according to claim 7, it is characterised in that the width of the first step knot terminal expansion area is 20 μm ~300 μm, depth be 0.8 μm~1.2 μm, the first step knot terminal expansion area second doping junction depth contour line (206B) Angle with the epi-layer surface (207) is 5~15 °.
- 9. structure according to claim 7, it is characterised in that the width of the second step knot terminal expansion area is 20 μm ~300 μm, depth be 0.4 μm~0.6 μm, the second step knot terminal expansion area the 3rd doping junction depth contour line (206C) Angle with the epi-layer surface (207) is 5~15 °.
- 10. structure according to claim 1, it is characterised in that the depth of the active area (205) is 0.5 μm~1 μm.
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| CN113658996A (en) * | 2021-08-20 | 2021-11-16 | 电子科技大学 | Transverse variable doping terminal structure and design method thereof |
| CN113658996B (en) * | 2021-08-20 | 2023-09-29 | 电子科技大学 | Transverse variable doping terminal structure and design method thereof |
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