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利用高精度x射线衍射和拉曼散射光谱 ,对MOCVD生长的不同Mg掺杂量的AlGaN薄膜的c轴晶格常数、摇摆曲线和拉曼频移进行测量发现 :当Mg掺杂剂量较小时 ,E2 模式向低频方向漂移表明张力应力有所增加 ,但是摇摆曲线和A1 (LO)模式半高宽减小表明薄膜质量有所提高 ;随着Mg掺杂剂量的增加 ,E2 模式反向漂移表明此时薄膜中存在压力应力 ,同时薄膜质量有所下降 .最后根据拉曼频移和应力改变进行拟合得出相应的线性表达式为Δσ=- 0 2 98+0 5 6 2·ΔE .
Using high-precision X-ray diffraction and Raman scattering spectra, the c-axis lattice constant, rocking curve and Raman shift of AlGaN thin films grown by MOCVD were measured. It was found that when Mg doping amount is small, The shift of E2 mode to low frequency indicates that the tension stress increases, but the rocking curve and the decrease of full width at half maximum (A1 (LO)) indicate that the film quality is improved. With the increase of Mg dopant, the backward shift of E2 mode indicates that When the film is under pressure stress, the quality of the film is decreased.Finally, the corresponding linear expression is obtained according to the Raman shift and the stress change as Δσ = - 0 2 98 + 0 5 6 2 · ΔE.