对在c面蓝宝石上用氢化物气相外延法(HVPE)生长的六方相纤锌矿结构的GaN膜中的应力进行了分析。高分辨X射线衍射(002)面和(102)面摇摆曲线扫描(半高宽数值分别为317和358角秒)表明生长的GaN膜具有较好的晶体质量。利用高分辨X射线衍射技术准确测量了制备的GaN膜的晶格常数,并计算得到GaN膜中面内双轴应变和面外双轴应变分别为3.37×10-4和-8.52×10-4,等静压应变为-7.61×10-5。拉曼光谱和激光光致发光谱测试表明HVPE-GaN外延膜具有较好的光学特性,利用拉曼光谱的E2模式特征峰和激光光致发光谱中近带边发射峰的频移定量计算了外延膜中的面内双轴压应力和等静压应力。两种方法得到的面内双轴压应力较为相符。
In the present paper,strain in GaN epitaxial layer grown by hydride vapor phase epitaxy (HVPE) was investigated by means of high-resolution X-ray diffraction (HRXRD), Raman spectra and photoluminescence (PL) measurements.Both the biaxial in-plane and out-of-plane strains (of the order of~10-4 and 10-4,respectively) and the hydrostatic strain component (of the order of~10-5) were extracted from HRXRD measurements.These values agreed well with the ones computed from the blue-shift of E 2 Raman mode and the near-band-edge PL peak.The results showed that strains in GaN layer were superposed by the biaxial strain and hydrostatic strain.