Direct growth of freestanding GaN on C-face SiC by HVPE.

Yuan Tian,Xiaopeng Hao,Lei Zhang,Qin Huo,Yongliang Shao,Yongzhong Wu,Yuanbin Dai

doi:10.1038/srep10748

Abstract

In this work, high quality GaN crystal was successfully grown on C-face 6H-SiC by HVPE using a two steps growth process. Due to the small interaction stress between the GaN and the SiC substrate, the GaN was self-separated from the SiC substrate even with a small thickness of about 100 μm. Moreover, the SiC substrate was excellent without damage after the whole process so that it can be repeatedly used in the GaN growth. Hot phosphoric acid etching (at 240 °C for 30 min) was employed to identify the polarity of the GaN layer. According to the etching results, the obtained layer was Ga-polar GaN. High-resolution X-ray diffraction (HRXRD) and electron backscatter diffraction (EBSD) were done to characterize the quality of the freestanding GaN. The Raman measurements showed that the freestanding GaN film grown on the C-face 6H-SiC was stress-free. The optical properties of the freestanding GaN layer were determined by photoluminescence (PL) spectra.

Highlights

GaN-based materials have attracted much interest as a material suitable for use in optoelectronic and electronic devices due to their excellent properties[1,2,3]
Due to the small interaction stress between GaN and the SiC substrate, the SiC substrate was excellent without damage after the whole process so that it can be repeatedly used in the GaN growth
The substrate was heated to 600 °C for deposition of low temperature GaN (LT-GaN) buffer layer, which was grown with 1800 sccm of NH3 and 10 sccm of GaCl for 30 min

Summary

Introduction

GaN-based materials have attracted much interest as a material suitable for use in optoelectronic and electronic devices due to their excellent properties[1,2,3]. Several papers about the direct growth of GaN layers on Si- face SiC substrates by HVPE9 have been reported. There have been few papers about the direct growth of GaN layers on C-face SiC substrates by HVPE as the growth of high quality GaN on C- face SiC is much more difficult[10].

Results

Conclusion