采用分子束外延(MBE)方法,通过反射高能电子衍射(RH EED)强度振荡测算生长速率,利用RHEED衍射实时监控生长过程,在InAs(001)和InP(001)单晶衬底上生长高In组分的InGaAs薄膜,并通过扫描隧道显微镜(STM)对其表面形貌和表面重构进行了细致分析,STM图片证实采用该方法获得的高In组分InGaAs薄膜处于高质量的平整状态.研究发现InGaAs与衬底之间的拉伸应力是促使薄膜表面呈现了大量的锯齿状边缘的主要原因;高分辨的STM分析还发现,高In组分的InGaAs薄膜是多种重构混合的表面,InGaAs/InAs是以β(2×4)重构为主,而InGaAs/InP是以(4×3)重构为主,它们在RHEED衍射图像上都是模糊的(2×3)或(4×3)/(2×3)表面重构.
InGaAs films with high In composition were prepared on InP (001) & InAs (001) substrate by molecular beam epitaxy (MBE).During the process of growing InGaAs,the growth rate and status was measured and monitored through reflection high energy electron diffraction (RHEED) oscillations and patterns respectively.After grown and annealed,the samples were transferred into scanning tunneling microscope (STM) to analyze the morphology and surface reconstruction.The STM images confirmed that the surface of InGaAs films were atomically flat.It is found that the stretch stress between InGaAs and substrate should play key role to shape the jagged edges on InGaAs surface.In despite of the surface of InGaAs films with high In composition have the same RHEED patterns which showed their reconstruction were (2 × 3) or (4 × 3)/(2 × 3),but from the high resolution STM images,it is considered that surface was a mixture reconstruction,β(2 × 4) was majority surface reconstruction of In0.90Ga0.10 As/InAs films while (4 × 3) was the mainly surface reconstruction of In0.53 Ga0.47 As/InP films.