A high-purity silicon carbide single crystal substrate

Abstract

The invention discloses a high-purity silicon carbide single crystal substrate and belongs to the field of semiconductor materials. The high-purity silicon carbide single crystal substrate at least comprises a silicon carbide single crystal substrate surface layer and a silicon carbide single crystal substrate main body layer, wherein intrinsic point defect concentration of the silicon carbide single crystal substrate surface layer is lower than that of the silicon carbide single crystal substrate main body layer, and the silicon carbide single crystal substrate has semi-insulativity. By meansof low intrinsic point defect concentration of the silicon carbide single crystal substrate surface layer, GaN fits better with a lattice of silicon carbide single crystals when the high-purity silicon carbide single crystals are taken as a substrate of a GaN epitaxial layer, so that the prepared GaN epitaxial layer has better quality; the silicon carbide single crystal substrate main body layerhas certain intrinsic point defect concentration, and semi-insulativity of the high-purity silicon carbide single crystal substrate can be kept.

Description

technical field [0001] The application relates to a high-purity silicon carbide single crystal substrate, which belongs to the field of semiconductor materials. Background technique [0002] Semi-insulating silicon carbide (silicon carbide) single crystal substrates are the preferred semiconductor substrate materials for GaN high-frequency microwave devices. This aspect depends on the excellent properties of semi-insulating silicon carbide single crystal substrates such as high resistivity, which can be prepared with excellent performance On the other hand, it depends on the high matching degree of the lattice constant of silicon carbide and GaN, which can make the heteroepitaxial layer obtain good crystal quality. [0003] In terms of implementation methods, there are two implementation methods for the preparation of semi-insulating silicon carbide single crystal substrates: doping and high purity. A large number of deep energy level centers are introduced by doping with a...

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Problems solved by technology

Intrinsic point defects are an indispensable feature to achieve the electrical properties of high-purity semi-insulating crystals, however, these point defects themselves will introduce large lattice stress, causing lattice distortion, and thus destroying the SiC single crystal lattice Integrity, to a certain extent, affects the lattice parameters of SiC single crystal

Considering that one of the main reasons why GaN uses silicon carbide single crystal substrates as epitaxy is the small mismatch of the lattice parameters between the two, the introduction of point defects will lead to an increase in the lattice fit between GaN and silicon carbide, This in turn reduces the quality of the GaN epitaxial layer

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