利用高频Plasma CVD在蓝宝石衬底上生长 立方GaN缓冲层及其光学性质

研究了采用高频PlasmaCVD技术在较低温度下(300—400℃)生长以GaN为基的Ⅲ-Ⅴ族氮化物的可行性，在蓝宝石衬底上生长了GaN缓冲层.热处理后的光致发光谱和X光衍射表明，生长的GaN缓冲层为立方相，带边峰位于3.15eV.在作者实验的范围内，最优化的TMGa流量为0.08sccm(TMAm=10sccm时)，XPS分析结果表明此时的Ga/N比为1.03.这是第一次在高Ⅴ/Ⅲ比下得到立方GaN.相同条件下石英玻璃衬底上得到的立方GaN薄膜，黄光峰很弱，晶体质量较好.

Optical Properties and Growth of Cubic GaN Buffer Layers on Sapphire by Radio Frequency Plasma CVD

GaN buffer layers were grown on sapphire substrates by RadioFrequency Plasma Chemical Vapor Deposition (RF plasma CVD)after post-deposition annealing.XRD and PL spectra indicate the GaN buffer layers are of cubic structure and probably polycrystalline.PL and XPS analyses show the most optimized TMGa/TMAm flow rate is 0.08sccm/10sccm according to the experiments,and at this point,the average composition of GaN buffer layer is Ga1.03N.It is the first time that cubic GaN films were achieved at such a high Ⅴ/Ⅲ rate.Compared with the PL spectrum of GaN on silica glass substrates,the crystal quality of GaN on sapphire substrates are worse,which is probably caused by the mismatch of lattices and the thermal conductivity between GaN films and sapphire substrate.