Epitaxy method for improving 4H-SiC basal plane dislocation conversion rate

Abstract

The invention discuses an epitaxy method for improving 4H-SiC basal plane dislocation conversion rate, which mainly solves the problem that the conversion rate that basal plane dislocation is converted into edge forming dislocation is low by adopting an corrosion method; the method comprises the following steps: (1) etch a 4H-SiC substrate by KOH, the etching temperature is 480-520 DEG C, and theetching time is 10-20min; (2) surface cleaning processing is carried out to the etched 4H-SiC substrate; (3) a 4H-SiC sample which carries out surface cleaning processing is placed in a CVD furnace cavity, vacuumizing is carried out to lead the pressure intensity in the furnace to reach 10-7Pa, the temperature in the furnace is raised to 1400-1500 DEG C, and hydrogen with 20-50l / min flow rate flows in for 5min, and then 8-15ml / min of propane flows in, the temperature is raised to 1580-1600 DEG C for 30-50 minutes under 80-100mbar of pressure; (4) when the temperature is reduced to 1550 plus / minus 5 under the condition of unchanged pressure, and epitaxy growth is carried out by silane flowing-in. the method can be applied to manufacturing of 4H-SiC homoepitaxy material.

Description

technical field [0001] The invention belongs to the technical field of microelectronics and relates to the manufacture of semiconductor materials, in particular to an improved epitaxy method for minimizing defects in silicon carbide crystals, which can be used in the manufacture of semiconductor device materials. Background technique [0002] Silicon carbide (SiC) has great potential for making various high-frequency and high-power devices with high temperature resistance due to its characteristics such as large band gap, high breakdown electric field, good thermal stability, high electron mobility and high electron saturation drift velocity. Semiconductor materials for applications where silicon devices are incapable. With the development of SiC epitaxial growth technology, the micropipe defect of the wafer is reduced to 1 / cm 2 , which has become the biggest opportunity for the development of SiC high-frequency power devices. At present, the main problem of SiC epitaxial ...

AI Technical Summary

Problems solved by technology

[0004] (1) Since there are two growth modes of lateral growth and step flow growth in the etching pit, when the lateral growth is dominant, the conversion rate of basal plane dislocations will increase, which will reduce the basal plane dislocation density, thereby improving the device performance. Reliability; when the step flow direction growth is dominant, the conversion rate of basal plane dislocations will be reduced, so that the basal plane dislocations generated in the substrate continue to extend into the epitaxial layer, reducing the reliability of the device;

[0005] (2) Since the microscopic growth mechanism is not yet clear, any growth mode in the etching pit is not easy to control in the process;

[0006] (3) Since polishing is required before secondary etching, more other defects will be introduced

Images