Conductive silicon carbide single crystal and preparation method thereof

Abstract

The invention provides a conductive silicon carbide single crystal. Doped elements comprise nitrogen and an element of which the atomic radius is greater than that of silicon. The resistivity of the conductive silicon carbide single crystal is from 0.01 [Omega]. cm to 0.05 [Omega]. cm; the doping concentration of the element having an atomic radius greater than the atomic radius of silicon is 0.1%-10% of the concentration of the nitrogen element. According to the silicon carbide crystal, on the basis of doping of a nitrogen element, through introduction of an element of which the atomic radius is greater than that of silicon and control of the concentrations of nitrogen and the element of which the atomic radius is greater than that of silicon, the resistivity is ensured to meet the requirements of a conductive silicon carbide single crystal substrate, lattice distortion caused by the size difference of nitrogen atoms and carbon atoms can be compensated, the internal stress of the crystal is reduced, and the dislocation density in the crystal is reduced. The invention also provides a preparation method of the conductive silicon carbide single crystal.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, in particular to a conductive silicon carbide single crystal and a preparation method thereof. Background technique [0002] Silicon carbide (SiC) single crystal is a wide bandgap semiconductor material with many characteristics such as large bandgap width, strong critical breakdown field, high thermal conductivity, and high saturation drift velocity. These characteristics make silicon carbide widely used in Manufacture high temperature, high frequency and high power electronic devices. [0003] In the existing silicon carbide conductive substrate, the main doping element is nitrogen, and the required resistivity is achieved by controlling the concentration of nitrogen atoms to a certain content. Nitrogen atoms in the crystal mainly occupy the positions of carbon atoms. Since nitrogen atoms are smaller than carbon atoms, the lattice distortion is caused, resulting in more dislocations ins...

AI Technical Summary

Problems solved by technology

According to the survey report on crystal defects and devices, BPD will cause poor oxide film of the device, resulting in insulation breakdown of the device. In addition, in bipolar devices, BPD will cause stacking defects, resulting in device performance degradation

TSD will also cause device leakage current and reduce the life of the gate oxide film

It can be seen that dislocations in silicon carbide single crystals will seriously affect the service life and life of devices, especially the existence of basal plane dislocations (BPDs) in silicon carbide substrates, which can easily transform into stacks during epitaxy. Stacking fault (SF), which seriously affects the performance of the device