3 in长波Ⅱ类超晶格分子束外延工艺优化研究

Research on Optimization of Molecular Beam Epitaxy Process of Long-Wave Type-Ⅱ Superlattice on 3-in Substrates

为提升大面阵Ⅱ类超晶格红外探测器的性能、产量和材料质量,对3 in长波InAs/GaSbⅡ类超晶格分子束外延(Molecular Beam Epitaxy,MBE)生长工艺优化进行了研究。结合反射式高能电子衍射(Reflection High-Energy Electron Diffraction,RHEED)条纹研究了不同的去氧化层温度和生长温度对3 in外延片质量的影响。使用光学显微镜、原子力显微镜(Atomic Force Microscopy,AFM)、表面颗粒检测仪、白光干涉仪、高分辨X射线衍射仪(High-Resolution X-Ray Diffractometer,HRXRD)以及X射线衍射谱模拟分别对外延片的表面形貌、均匀性和晶格质量进行了表征。优化后外延片1μm以上缺陷的密度为316cm^(-2),粗糙度为0.37 nm,总厚度偏差(Total Thickness Variation,TTV)为19.6μm,77 K下截止波长为9.98μm。在2 in长波Ⅱ类超晶格分子束外延生长工艺的基础上,研究了增大GaSb衬底尺寸后相应生长条件的变化情况。这对尺寸增大后Ⅲ-Ⅴ族分子束外延工艺条件的调整具有参考意义,也为锑基Ⅱ类超晶格红外探测器的面阵规模、质量和产能提升奠定了基础。

In order to improve the performance,output and material quality of the large area array type-Ⅱsuperlattice infrared detector,the optimal molecular beam epitaxy(MBE)growth condition of the long-wave InAs/GaSb type-Ⅱsuperlattice on 3-in GaSb substrate was studied.Combined with reflection high-energy electron diffraction(RHEED)fringes,the effects of different deoxidation temperature and growth temperature on the quality of 3-in epitaxial wafers were studied.The surface morphology,uniformity and lattice quality of the wafers were characterized by optical microscopy,atomic force microscopy(AFM),wafer defect inspection system,white light diffractometry,high-resolution X-ray diffractometer(HRXRD),and X-ray diffraction simulations.After optimization,the density of defects above 1μm of the epitaxial wafer is 316 cm^(-2),the roughness is 0.37 nm,the total thickness variation(TTV)is 19.6μm,and the cut-off wavelength at 77 K is 9.98μm.Based on the molecular beam epitaxial growth process of 2-in long-wave type-Ⅱsuperlattice,the changes in the growth conditions after increasing the size of the GaSb substrate were studied.This is of reference significance for the adjustment of the conditions ofⅢ-Ⅴmolecular beam epitaxy process after the size is increased.It also lays the foundation for the scale,quality and productivity improvement of the antimony-based type-Ⅱsuperlattice infrared detector array.