Title of Paper:Improvements of epitaxial quality and stress state of GaN grown on SiC by in situ SiNx interlayer

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Date of Publication:2016-10-01

Journal:JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS

Included Journals:SCIE、EI、Scopus

Volume:27

Issue:10

Page Number:10003-10009

ISSN No.:0957-4522

Abstract:In this study, 4.5 mu m thick GaN films with graded AlxGa1-xN/AlN buffer and SiNx interlayer were prepared on 6H-SiC substrates by metal-organic chemical vapor deposition. To determine the effects of SiNx interlayer on epitaxial quality and stress state of GaN films, a series of comparative experiments were carried out by changing the deposition time and the insert location of SiNx interlayer. By optimizing growth conditions of SiNx interlayer, the full width at half maximum values of and rocking curves of GaN films were improved to 142 and 170 arcsec, respectively. A crack-free GaN film with a small root-mean-squared roughness of 0.21 +/- 0.02 nm was achieved. Simultaneously, the reduction in threading dislocation density of GaN films was confirmed by using wet etching method. In addition, stress values in GaN films were investigated by Raman and low-temperature photoluminescence spectra, which indicated that the lower tensile stress in GaN film, the higher the film's crystallinity.