CN104851781B - Preparation method of N-type low-deflection-angle silicon carbide epitaxial wafer - Google Patents
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- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 55
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 45
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 238000007664 blowing Methods 0.000 claims abstract description 33
- 238000005530 etching Methods 0.000 claims abstract description 31
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 7
- 239000002019 doping agent Substances 0.000 claims description 29
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 23
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 23
- 229910052799 carbon Inorganic materials 0.000 claims description 23
- 229910052710 silicon Inorganic materials 0.000 claims description 23
- 239000010703 silicon Substances 0.000 claims description 23
- 229910003822 SiHCl3 Inorganic materials 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 8
- 230000007547 defect Effects 0.000 abstract description 5
- 239000002245 particle Substances 0.000 abstract description 3
- 230000008569 process Effects 0.000 abstract description 3
- 238000009776 industrial production Methods 0.000 abstract description 2
- 239000013049 sediment Substances 0.000 abstract 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 25
- 235000012431 wafers Nutrition 0.000 description 25
- 239000007789 gas Substances 0.000 description 15
- 238000010438 heat treatment Methods 0.000 description 15
- 229910052739 hydrogen Inorganic materials 0.000 description 15
- 239000001257 hydrogen Substances 0.000 description 15
- 238000004630 atomic force microscopy Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 230000003746 surface roughness Effects 0.000 description 5
- 238000004220 aggregation Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 238000000407 epitaxy Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02367—Substrates
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- H01L21/02373—Group 14 semiconducting materials
- H01L21/02378—Silicon carbide
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- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
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Abstract
The invention provides a preparation method of an N-type low-deflection-angle silicon carbide epitaxial wafer, which comprises the following steps of: preparing a substrate, etching the substrate on line, growing a buffer layer and growing an epitaxial layer, wherein the epitaxial layer is grown by adopting a method of 'growing, etching, blowing and regrowing'. The method effectively reduces the dislocation density of the basal plane and the sediment in the cavity in the process of growing the N-type low-deflection-angle silicon carbide epitaxial wafer, thereby reducing the triangular defects caused by foreign particles, improving the quality of the silicon carbide epitaxial material, having low processing cost and being suitable for industrial production.
Description
Technical Field
The invention relates to a preparation method of a semiconductor material, in particular to a preparation method of an N-type low-deflection-angle silicon carbide epitaxial wafer.
Background
The silicon carbide has good chemical inertness, high temperature resistance and radiation resistance, and has great application potential in the field of high-power electronics. Silicon carbide is a material with a homogenous variety of crystalline forms, more than 250 of which have been found. Among many SiC polytypes, 4H-SiC has a large forbidden band width (3.26eV) and a high mobility (900 cm)2Vs) and a relatively small anisotropy are considered to be more suitable for manufacturing high power high back voltage electronic devices.
The existing technology of step control epitaxy for epitaxial growth of SiC with deflection angles of 8 degrees and 4 degrees is essentially the flow of atomic steps. The technology not only effectively controls the crystal form of SiC, but also reduces the epitaxial growth temperature of SiC, and the SiC epitaxial material with a bright surface is grown at 1500 ℃, so that the epitaxial growth temperature is reduced by nearly 300 ℃, and the purpose of reducing the cost is achieved.
As the SiC substrate wafer diameter increases, from 2 inches to 3 inches and 4 inches, or even 6 inches, the magnitude of the off-direction angle is important for SiC cost reduction, since the larger the angle, the fewer the number of wafers that can be obtained from a single SiC boule. Furthermore, from the standpoint of SiC epitaxy, the magnitude of the off-orientation angle also has a large impact on the quality of the epitaxial material.
While there is growing interest in the epitaxial growth of SiC on low off-angle substrates in light of the current state of wafer size development, the literature reports that the surface roughness of low off-angle epitaxial growth of silicon carbide is difficult to control, and that ultra-thick epitaxial layers of silicon carbide are required for high voltage power electronics. Therefore, the problem to be solved for growing the ultra-thick epitaxial layer with a low off angle is to control the surface appearance of the epitaxial wafer while reducing defects.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method for preparing N-type low off-angle silicon carbide epitaxy, which can reduce the dislocation density of the basal plane, reduce the deposit in the cavity, and effectively reduce the step aggregation and reduce the surface roughness.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of an N-type low-deflection-angle silicon carbide epitaxial wafer comprises the following steps:
1) etching the substrate on line: placing a silicon carbide substrate with an off-angle of less than 8 degrees in a reaction chamber, vacuumizing, and introducing H at the flow rates of 40-80L/min and 5-10L/min respectively2And HCl, etching for 5-20 min under the pressure of 20-60mbar and the temperature of 1510-1710 ℃;
2) and (3) growing the buffer layer: stopping introducing HCl, and introducing a silicon source, a carbon source and N at the flow rates of 6-10 mL/min, 3-5 mL/min and 1500-1800 mL/min respectively2A dopant, growing a buffer layer with the thickness of 0.2-5 mu m at the temperature of 1500-1680 ℃ and under the pressure of 20-100 mbar;
3) growth of epitaxial layers
a, growing: introducing H at the flow rates of 40-80L/min, 10-40 mL/min, 5-20 mL/min and 800-1500 mL/min respectively2Growing a silicon source, growing a carbon source and N2A dopant, and growing an epitaxial layer with the thickness of 5-50 microns at the temperature of 1500-1680 ℃ and the pressure of 20-100 mbar;
b, etching: stopping respectively introducing the silicon source, the carbon source and the N2In aMaintaining the temperature at 1510-1710 ℃ for 2-5 min; introducing HCl at the flow rate of 5-10L/min, and etching for 2-5 min;
c, blowing: h is blown at the flow rate of 45-90 mL/min after HCl introduction is stopped22～10min；
d, regrowing: and (c) repeating the step (a) to grow the epitaxial layer to 5-200 mu m.
According to a first preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the off-angle of the silicon carbide substrate is 2 degrees.
According to a second preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the off-angle of the silicon carbide substrate is 4 degrees.
According to the third preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the substrate material is 4H-SiC or 6H-SiC.
According to a fourth preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the silicon source for growing is SiH4Or SiHCl3The growth carbon source is C2H4Or C3H8。
According to a fifth preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the steps b to d in the step 3) are repeated.
According to the sixth preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the repetition time is 0-30 times.
According to the seventh preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the repetition time is 0-10 times.
According to the eighth preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the growth thickness of the epitaxial layer is 5-30 microns.
According to the ninth preferred technical scheme of the preparation method of the N-type low-off-angle silicon carbide epitaxial wafer, the growth thickness of the epitaxial layer is 30-200 microns.
Compared with the closest prior art, the technical scheme provided by the invention has the following excellent effects:
1. the silicon carbide substrate provided by the invention has large corrosion pits of basal plane dislocation, so that the basal plane dislocation is more easily converted into screw dislocation in an epitaxial process, and the aim of reducing the basal plane dislocation density is fulfilled;
2. reducing surface defect particles and defects caused by the particles, especially triangular defects;
3. due to the etching effect, the cleaning period of the growth cavity is prolonged, the growth cost is greatly reduced, and the growth efficiency is improved;
4. the method provided by the invention has the advantages of simple manufacturing method and good process repeatability, and is suitable for industrial production;
5. the ultra-thick silicon carbide epitaxial surface provided by the invention has no step aggregation phenomenon.
Drawings
FIG. 1: the invention is a flow diagram.
FIG. 2: surface appearance of epitaxial wafer prepared by traditional method
FIG. 3: example 1 atomic force microscopy of epitaxial wafers
FIG. 4: example 2 atomic force microscopy of epitaxial wafers
FIG. 5: example 3 atomic force microscopy of epitaxial wafers
FIG. 6: example 4 atomic force microscopy of epitaxial wafers
FIG. 7: example 5 atomic force microscopy of epitaxial wafers
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
Example 1
A preparation method of an N-type silicon carbide epitaxial wafer with low deflection angle and thickness of 15 mu m comprises the following steps:
1) etching the substrate on line: preparing a 4H-SiC substrate with a deflection angle of 4 degrees, vacuumizing, introducing hydrogen gas with the flow rate of 40L/min and HCl with the flow rate of 5L/min, and maintaining the pressure in a reaction chamber at 40mbar and the temperature at 1680 ℃ for 5 minutes;
2) and (3) growing the buffer layer: stopping introducing HCl, cooling to 1650 ℃, and introducing flowSiH of 6mL/min4And 3mL/min of C3H8At a flow rate of 1500mL/min2Is used as a dopant, the growth pressure is 40mbar, and a buffer layer with the thickness of 0.4 mu m is grown;
3) growth of epitaxial layers
a, growing: hydrogen gas at a flow rate of 40L/min and SiH at a flow rate of 10mL/min4And C of 5mL/min3H8Introducing into a reaction chamber, maintaining the temperature at 1650 deg.C and the pressure at 40mbar, and introducing N at a flow rate of 800mL/min2As a dopant, an epitaxial layer with the thickness of 6 μm is grown;
b, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
c, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 5 minutes;
d, regrowing: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 15 mu m.
Example 2
An N-type silicon carbide epitaxial preparation method with low deflection angle and thickness of 30 mu m comprises the following steps:
1) etching the substrate on line: preparing a 4H-SiC substrate with a deflection angle of 2 degrees, vacuumizing, introducing hydrogen gas with the flow rate of 40L/min and HCl with the flow rate of 5L/min, and maintaining the pressure in a reaction chamber at 40mbar and the temperature at 1680 ℃ for 5 minutes;
2) and (3) growing the buffer layer: stopping introducing HCl, cooling to 1650 ℃, and introducing SiH with the flow of 6mL/min4And 3mL/min of C3H8At a flow rate of 1500mL/min2Is used as dopant, the growth pressure is 40mbar, and a buffer layer with the thickness of 1 μm is grown;
3) growth of epitaxial layers
a, growing: hydrogen gas at a flow rate of 40L/min and SiH at a flow rate of 10mL/min4And C of 5mL/min3H8Introducing into a reaction chamber, maintaining the temperature at 1650 deg.C and the pressure at 40mbar, and introducing N at a flow rate of 800mL/min2As a dopant, an epitaxial layer with the thickness of 10 μm is grown;
b, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
c, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 5 minutes;
d, regrowing: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 20 μm.
e, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
f, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
g, regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 30 μm.
Example 3
An N-type silicon carbide epitaxial preparation method with low deflection angle and thickness of 80 mu m comprises the following steps:
1) etching the substrate on line: preparing a 4H-SiC substrate with a deflection angle of 4 degrees, vacuumizing, introducing hydrogen gas with the flow rate of 40L/min and HCl with the flow rate of 5L/min, and maintaining the pressure in a reaction chamber at 40mbar and the temperature at 1680 ℃ for 5 minutes;
2) and (3) growing the buffer layer: stopping introducing HCl, cooling to 1650 ℃, and introducing SiH with the flow of 6mL/min4And 3mL/min of C3H8At a flow rate of 1500mL/min2Is used as a dopant, the growth pressure is 40mbar, and a buffer layer with the thickness of 1.5 mu m is grown;
3) growth of epitaxial layers
a, growing: hydrogen gas at a flow rate of 40L/min and SiH at a flow rate of 10mL/min4And C of 5mL/min3H8Introducing into a reaction chamber, maintaining the temperature at 1650 deg.C and the pressure at 40mbar, and introducing N at a flow rate of 800mL/min2As a dopant, an epitaxial layer with the thickness of 10 μm is grown;
b, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
c, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 2 minutes;
d, regrowing: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 30 μm.
e, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
f, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
g, regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 50 μm.
h, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
i blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
j regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 80 μm.
Example 4
An N-type silicon carbide epitaxial preparation method with low deflection angle and thickness of 100 mu m comprises the following steps:
1) etching the substrate on line: preparing a 4H-SiC substrate with a deflection angle of 2 degrees, vacuumizing, introducing hydrogen gas with the flow rate of 40L/min and HCl with the flow rate of 5L/min, and maintaining the pressure in a reaction chamber at 40mbar and the temperature at 1680 ℃ for 5 minutes;
2) and (3) growing the buffer layer: stopping introducing HCl, cooling to 1650 ℃, and introducing SiH with the flow of 6mL/min4And 3mL/min of C3H8At a flow rate of 1500mL/min2Is used as a dopant, the growth pressure is 40mbar, and a buffer layer with the thickness of 3 mu m is grown;
3) growth of epitaxial layers
a, growing: hydrogen gas at a flow rate of 40L/min and SiH at a flow rate of 10mL/min4And C of 5mL/min3H8Introducing into a reaction chamber, maintaining the temperature at 1650 deg.C and the pressure at 40mbar, and introducing N at a flow rate of 800mL/min2As a dopant, an epitaxial layer with the thickness of 10 μm is grown;
b, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
c, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 2 minutes;
d, regrowing: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 40 μm.
e, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
f, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
g, regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 70 μm.
h, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
i blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 2 minutes;
j regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 100 mu m.
Example 5
An N-type silicon carbide epitaxial preparation method with low deflection angle and thickness of 180 mu m comprises the following steps:
1) etching the substrate on line: preparing a 4H-SiC substrate with a deflection angle of 2 degrees, vacuumizing, introducing hydrogen gas with the flow rate of 40L/min and HCl with the flow rate of 5L/min, and maintaining the pressure in a reaction chamber at 40mbar and the temperature at 1680 ℃ for 5 minutes;
2) and (3) growing the buffer layer: stopping introducing HCl, cooling to 1650 ℃, and introducing SiH with the flow of 6mL/min4And 3mL/min of C3H8At a flow rate of 1500mL/min2Is used as a dopant, the growth pressure is 40mbar, and a buffer layer with the thickness of 5 mu m is grown;
3) growth of epitaxial layers
a, growing: hydrogen gas at a flow rate of 40L/min and SiH at a flow rate of 10mL/min4And C of 5mL/min3H8Introducing into a reaction chamber, maintaining the temperature at 1650 deg.C and the pressure at 40mbar at 800mL/minN of flow2As a dopant, an epitaxial layer with the thickness of 10 μm is grown;
b, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
c, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
d, regrowing: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 30 μm.
e, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 12 minutes;
f, blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
g, regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 50 μm.
h, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 2 minutes;
i blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 5 minutes;
j regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 80 μm.
k, etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
l blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 2 minutes;
and m regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 120 mu m.
n etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
and o blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
and p regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 150 μm.
q etching: stopping introducing the silicon source, the carbon source and the doping agent, heating to 1680 ℃, and maintaining for 2 minutes; introducing HCl with the flow rate of 5L/min, and maintaining for 1 minute;
r blowing: stopping introducing HCl, adjusting the hydrogen flow to 45mL/min, and blowing for 3 minutes;
s regrowth: setting the gas flow, temperature and pressure consistent with the step a, and continuing to grow the epitaxial layer to 180 mu m.
Surface roughness test
The roughness of the silicon carbide epitaxial wafers prepared in examples 1 to 5 of the present invention was measured by an atomic force microscope, and the results are shown in fig. 3 to 7, and compared with the epitaxial wafers prepared by the conventional method, the surface roughness was free from the step aggregation phenomenon, and the root mean square of the surface roughness was within 0.5 nm.
The above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and it should be understood by those skilled in the art that the specific embodiments of the present invention can be modified or substituted with equivalents with reference to the above embodiments, and any modifications or equivalents without departing from the spirit and scope of the present invention are within the scope of the claims to be appended.
Claims (1)
1. A preparation method of an N-type low-deflection-angle silicon carbide epitaxial wafer comprises the following steps:
1) etching the substrate on line: placing a silicon carbide substrate with an off-angle of less than 8 degrees in a reaction chamber, vacuumizing, and introducing H at the flow rates of 40-80L/min and 5-10L/min respectively2And HCl, etching for 5-20 min under the pressure of 20-60mbar and the temperature of 1510-1710 ℃;
2) and (3) growing the buffer layer: stopping introducing HCl, and introducing a silicon source, a carbon source and N at the flow rates of 6-10 mL/min, 3-5 mL/min and 1500-1800 mL/min respectively2A dopant, growing a buffer layer with the thickness of 0.2-5 mu m at the temperature of 1500-1680 ℃ and under the pressure of 20-100 mbar;
3) growth of epitaxial layers
a, growing: is divided intoIntroducing H at flow rates of 40-80L/min, 10-40 mL/min, 5-20 mL/min and 800-1500 mL/min respectively2Growing a silicon source, growing a carbon source and N2A dopant, and growing an epitaxial layer with the thickness of 5-50 microns at the temperature of 1500-1680 ℃ and the pressure of 20-100 mbar;
b, etching: stopping respectively introducing the silicon source, the carbon source and the N2Maintaining the temperature at 1510-1710 ℃ for 2-5 min; introducing HCl at the flow rate of 5-10L/min, and etching for 2-5 min;
c, blowing: h is blown at the flow rate of 45-90 mL/min after HCl introduction is stopped22～10min；
d, regrowing: setting the gas flow, the temperature and the pressure consistent with those in the step a, and repeating the step a to grow the epitaxial layer to 5-200 mu m;
the deflection angle of the silicon carbide substrate is 2 degrees;
repeating steps b to d in step 3);
the substrate material is 4H-SiC or 6H-SiC;
the growing silicon source is SiH4Or SiHCl3The growth carbon source is C2H4Or C3H8；
The repetition frequency is 0-10 times;
the growth thickness of the epitaxial layer is 30-100 mu m.
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| CN105244255B (en) * | 2015-08-27 | 2019-03-05 | 中国电子科技集团公司第十三研究所 | A kind of silicon carbide epitaxy material and its production method |
| CN105354352B (en) * | 2015-09-25 | 2019-06-21 | 国网智能电网研究院 | A kind of 8 ° of drift angle three dimensional atomic structure models of 4H-SiC material and its construction method and application |
| CN107068539B (en) * | 2016-12-15 | 2019-11-22 | 中国电子科技集团公司第五十五研究所 | The method for reducing silicon carbide epitaxy base plane dislocation density |
| CN106910673B (en) * | 2017-03-02 | 2019-05-21 | 东莞市天域半导体科技有限公司 | A kind of epitaxy method reducing SiC epitaxial wafer surface triangles defect |
| CN111005068A (en) * | 2019-12-09 | 2020-04-14 | 中国电子科技集团公司第五十五研究所 | Method for growing high-surface-quality ultra-thick IGBT structure silicon carbide epitaxial material |
| CN117637444B (en) * | 2024-01-25 | 2024-06-07 | 希科半导体科技(苏州)有限公司 | Epitaxial growth method |
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| US7018554B2 (en) * | 2003-09-22 | 2006-03-28 | Cree, Inc. | Method to reduce stacking fault nucleation sites and reduce forward voltage drift in bipolar devices |
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