Preparation method of high-quality semi-insulating silicon carbide single crystal and substrate doped with a small amount of vanadium

Abstract

The invention discloses preparation methods of high-quality semi-insulating silicon carbide single crystal doped with a small amount of vanadium and a high-quality semi-insulating silicon carbide single crystal substrate doped with a small amount of vanadium, and belongs to the field of semiconductor materials. The preparation method of the semi-insulating silicon carbide single crystal comprisesthe steps: removing impurities of a thermal field device, mixing materials, performing crystal growth and conducting annealing treatment. The preparation method of the semi-insulating silicon carbidesingle crystal has low technical cost and capital cost, and the resistivity of the prepared silicon carbide single crystal depends on residual shallow energy level impurities and a small amount of vanadium element; since lattice positions are occupied by the impurities, the impurities have high thermal stability, it means that the crystal can have highly stable resistivity; and since the silicon carbide single crystal substrate prepared from the silicon carbide single crystal has high resistivity uniformity and low stress, so that the silicon carbide single crystal substrate has excellent surface quality, and the stability and consistency of the substrate quality in the subsequent epitaxial process are ensured.

Description

technical field [0001] The application relates to a method for preparing a high-quality semi-insulating silicon carbide single crystal doped with a small amount of vanadium and a substrate, and belongs to the field of semiconductor materials. Background technique [0002] Semi-insulating silicon carbide (SiC) single crystal substrate has become the preferred semiconductor material for GaN-based high-frequency microwave devices due to its excellent physical properties such as large band gap, high resistivity and thermal conductivity, and strong breakdown field. With the continuous development of 5G technology, the demand for semi-insulating silicon carbide single crystal substrates on the market side continues to expand. More importantly, batch commercial applications have also put forward higher quality requirements for silicon carbide semi-insulating single crystal substrates. high demands. [0003] The semi-insulating silicon carbide single crystal that has been industria...

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Problems solved by technology

However, the intrinsic point defect has a high migration rate in the crystal, and at a certain temperature (such as the temperature condition of GaN epitaxial layer preparation), migration, diffusion and annihilation will occur, which will cause the instability of the substrate resistivity, Also affect the stability of device performance

[0005] The vanadium concentration [V] in doped semi-insulating silicon carbide single crystal is usually 1×10 17 ~1×10 18 cm -3 , corresponding to a nitrogen concentration [N] higher than 10 17 cm -3 The high-concentration vanadium doping in the preparation process has high technical barriers, and it is easy to form a large number of defects and uncontrollable shallow energy level impurity concentration in the prepared crystal, resulting in uncontrollable crystal quality

[N] in high-purity semi-insulating silicon carbide single crystal is 10 15 cm -3 order of magnitude, the corresponding point defect concentration is 1×10 15 cm -3 Level and above, the removal of shallow energy level impurities such as nitrogen in the preparation process requires high technical and capital costs

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