A method for reducing Si concentration at the interface between gan substrate and epitaxial layer

Abstract

The present invention provides a method for reducing Si concentration at the interface between a GaN substrate and an epitaxial layer, including S1. selecting a GaN homogenous substrate, and pre-processing the GaN substrate to expose the atomic step morphology; S2. epitaxy in an epitaxial system Grow GaN-based material; S3. Continue to heat the GaN-based material with protective gas at not lower than 500° C. to increase the driving force of atomic diffusion at the interface. This method can effectively reduce the GaN substrate and the epitaxial layer. The Si impurity concentration at the interface reduces the leakage current of the device prepared based on this method, which is beneficial to improve the performance of the prepared device.

Description

technical field [0001] The invention belongs to the field of semiconductor device technology, in particular to a method for reducing the Si concentration at the interface between a GaN substrate and an epitaxial layer. Background technique [0002] As a wide band gap semiconductor material, GaN-based semiconductor materials have the advantages of direct band gap, wide band gap, high breakdown field strength, as well as spontaneous polarization and piezoelectric polarization characteristics. ideal material. At present, GaN-based materials are mainly divided into two types, one is sapphire (Al 2 O 3 ), silicon carbide (SiC) and silicon (Si) and other hetero-substrates for epitaxial growth of GaN materials and device structures, however, due to the gap between GaN-based materials (including GaN, AlGaN, AlN, InGaN, InN) and the heterosubstrate There is a large lattice mismatch and thermal mismatch, which causes a large number of dislocations in the epitaxial material, which a...

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Problems solved by technology

Si is one of the main n-type doping sources of GaN-based materials. The preparation of GaN homogeneous substrates involves complex processes such as grinding and polishing, which will cause high concentrations of Si atoms on the surface of GaN homogeneous substrates. , a high concentration of Si atoms still exists at the interface between the GaN homogeneous substrate and the epitaxial layer, resulting in a great increase in the carrier concentration at the interface, reducing the material resistivity, causing serious leakage of the device substrate, and affecting the performance of the prepared device. cause adverse effects

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