Preparation method of N-type low-drift-angle silicon carbide epitaxial wafer

A technology of low-off-angle silicon carbide and epitaxial wafers, applied in semiconductor/solid-state device manufacturing, electrical components, circuits, etc., can solve problems such as difficult control of surface roughness, achieve extended cleaning cycle, reduce basal plane dislocation density, The effect of reducing the cost of growth

Active Publication Date: 2015-08-19
GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] According to the development status of the wafer size, people pay more and more attention to the epitaxial growth of SiC on the substrate with low off-angle orientation, and according to the literature reports, the surface roughness of SiC low-off-angle epitaxial growth is difficult to control. In terms of devices, an ultra-thick silicon carbide epitaxial layer is required

Method used

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  • Preparation method of N-type low-drift-angle silicon carbide epitaxial wafer
  • Preparation method of N-type low-drift-angle silicon carbide epitaxial wafer
  • Preparation method of N-type low-drift-angle silicon carbide epitaxial wafer

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Embodiment 1

[0040] A method for preparing an N-type low off-angle silicon carbide epitaxial wafer with a thickness of 15 μm, comprising the following steps:

[0041] 1) On-line etching substrate: Prepare a 4H-SiC substrate with an off angle of 4°, vacuumize it, and feed in hydrogen gas at a flow rate of 40L / min and HCl at a flow rate of 5L / min. The pressure in the reaction chamber is 40mbar and the temperature is 1680°C , for 5 minutes;

[0042] 2) Growth of the buffer layer: Stop feeding HCl, lower the temperature to 1650°C, and feed SiH with a flow rate of 6mL / min 4 and 3mL / min of C 3 h 8 , with the flow rate of 1500mL / min N 2 As a dopant, the growth pressure is 40mbar, and a buffer layer with a thickness of 0.4μm is grown;

[0043] 3) Growth of epitaxial layer

[0044] a Growth: 40L / min flow rate of hydrogen, 10mL / min SiH 4 and 5mL / min of C 3 h 8 Pass into the reaction chamber, keep the temperature at 1650°C, the pressure at 40mbar, and the N at a flow rate of 800mL / min 2 As a...

Embodiment 2

[0049] A method for preparing N-type low off-angle silicon carbide epitaxy with a thickness of 30 μm, comprising the following steps:

[0050] 1) On-line etching of the substrate: prepare a 4H-SiC substrate with an off-angle of 2°, vacuumize it, feed in hydrogen gas at a flow rate of 40L / min and HCl at a flow rate of 5L / min, the pressure in the reaction chamber is 40mbar, and the temperature is 1680°C , for 5 minutes;

[0051] 2) Growth of the buffer layer: Stop feeding HCl, lower the temperature to 1650°C, and feed SiH with a flow rate of 6mL / min 4 and 3mL / min of C 3 h 8 , with the flow rate of 1500mL / min N 2 As a dopant, the growth pressure is 40mbar, and a buffer layer with a thickness of 1 μm is grown;

[0052] 3) Growth of epitaxial layer

[0053] a Growth: 40L / min flow rate of hydrogen, 10mL / min SiH 4 and 5mL / min of C 3 h 8 Pass into the reaction chamber, keep the temperature at 1650°C, the pressure at 40mbar, and the N at a flow rate of 800mL / min 2 As a dopant, g...

Embodiment 3

[0061] A method for preparing N-type low off-angle silicon carbide epitaxy with a thickness of 80 μm, comprising the following steps:

[0062] 1) On-line etching of the substrate: Prepare a 4H-SiC substrate with an off-angle of 4°, vacuumize it, and feed in hydrogen gas at a flow rate of 40L / min and HCl at a rate of 5L / min. The pressure in the reaction chamber is 40mbar and the temperature is 1680°C , for 5 minutes;

[0063] 2) Growth of the buffer layer: Stop feeding HCl, lower the temperature to 1650°C, and feed SiH with a flow rate of 6mL / min 4 and 3mL / min of C 3 h 8 , with the flow rate of 1500mL / min N 2 As a dopant, the growth pressure is 40mbar, and a 1.5μm thick buffer layer is grown;

[0064] 3) Growth of epitaxial layer

[0065] a Growth: 40L / min flow rate of hydrogen, 10mL / min SiH 4 and 5mL / min of C 3 h 8 Pass into the reaction chamber, keep the temperature at 1650°C, the pressure at 40mbar, and the N at a flow rate of 800mL / min 2 As a dopant, grow a 10μm th...

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Abstract

The invention provides a preparation method of an N-type low-drift-angle silicon carbide epitaxial wafer. The method comprises the following steps: preparation of a substrate, online etching of the substrate, growing of a buffer layer and the growing of an epitaxial layer, wherein the growing of the epitaxial layer employs a method of "growing, etching, blowing and regrowing". The method provided by the invention effectively reduces the base dislocation density and reduces deposits in a cavity during the process of growing the N-type low-drift-angle silicon carbide epitaxial wafer, accordingly reduces the triangle defect caused by foreign particles, improves the quality of a silicon carbide epitaxial material, and is low in processing cost, thereby being suitable for industrial production.

Description

technical field [0001] The invention relates to a method for preparing a semiconductor material, in particular to a method for preparing an N-type low off-angle silicon carbide epitaxial wafer. Background technique [0002] Silicon carbide has good chemical inertness, high temperature resistance and radiation resistance, and has great application potential in the field of high-power power electronics. Silicon carbide is a homogenous polymorphic material, and more than 250 crystalline forms have been discovered. Among the many SiC polytypes, 4H-SiC is known for its large bandgap (3.26eV) and high mobility (900cm 2 / Vs) and smaller anisotropy are considered to be more suitable for the manufacture of high-power and high-backvoltage electronic devices. [0003] The essence of the current SiC 8° and 4° off-angle epitaxial growth "step control epitaxy" technology is the flow of atomic steps. This technology not only effectively controls the crystal form of SiC, but also reduces...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/02
CPCH01L21/02378H01L21/0243
Inventor 钮应喜杨霏
Owner GLOBAL ENERGY INTERCONNECTION RES INST CO LTD
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