We report the Si-doping-induced relaxation of residual stress in GaN epitaxial layers grown on (0001) sapphire substrate by the metalorganic vapor phase epitaxy technique. Micro-Raman spectroscopy is used to assess stress situation in the films with systematically modulated doping concentration from up to As the Si-doping concentration increases, a monotonic decrease of the phonon frequency is observed, which signifies gradual relaxation of the stress in the film. The layers are fully relaxed when electron concentration exceeds The linear coefficient of shift in Raman frequency (ω) induced by the in-plane biaxial compressive stress is estimated to be We suggest that Si doping increases density of misfit dislocation, judging from linewidth of x-ray rocking curve.
Stress relaxation in Si-doped GaN studied by Raman spectroscopy
In-Hwan Lee, In-Hoon Choi, Cheul-Ro Lee, Eun-joo Shin, Dongho Kim, Sam Kyu Noh, Sung-Jin Son, Ki Yong Lim, Hyung Jae Lee; Stress relaxation in Si-doped GaN studied by Raman spectroscopy. J. Appl. Phys. 1 June 1998; 83 (11): 5787–5791. https://doi.org/10.1063/1.367501
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