Impurities of Homoepitaxy Interface on Bulk GaN Substrate

Abstract

Abstract: Homoepitaxy on bulk GaN substrate has significant advantages. However, accumulation of impurities on the regrowth interface has always been a problem that plagues the wide application of homoepitaxial, especially for electronic devices, which will bring channel effect, and for laser applications, which will affect the light field distribution in the resonator. In this paper, the in-situ treatment of metal-organic chemical vappor deposition (MOCVD) growth has achieved effective inhibition of the accumulation of interfacial impurities. The study found that the main impurities on the interface are C, H, O and Si, of which C, H, O can be removed by in-situ thermal cleaning. The problem of interface Si accumulation is mainly caused by exposure to air during the preservation of the substrate. During the growth process, the etching of the substrate by the carrier gas will release impurity elements which will accumulate at the regrowth interface. High Si background content and unstable N face of the GaN substrate are also sources of regrowth interface impurities. This paper systematically clarified the formation mechanism of interface impurities and proposed solutions.

Key words: GaN substrate, regrow interface, interfacial impurity, source of impurity, homoepitaxy, Si accumulation

CLC Number:

O734
TN304

SHAO Kaiheng, XIA Songyuan, ZHANG Yumin, WANG Jianfeng, XU Ke. Impurities of Homoepitaxy Interface on Bulk GaN Substrate[J]. Journal of Synthetic Crystals, 2021, 50(3): 441-446.

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