The Heteroepitaxy Of GaAs/Si And Research On InAs Quantum Dots On Si Substrate

Electronic information industry is a strategic, basic and pillar industries, it’s also the booster of economic development in downturn. The major re-quirements of our country is how to make the national information infrastruc-ture stronger function, higher reliability, smaller and lighter device, simpler system design and stronger network flexibility, and the key to solve these prob-lems is optolectronic integrated. Due to the mature manufacture of microelec-tronic devices based Si substrate and the efficient luminescence performance of III-V material, Si and III-V semiconductor material is the two material system of microelectronics and optoelectronics devices. The key to realize optoelec-tronic integration is to solve the problem of Si and III-V integration, especially the integration of Si and GaAs. This thesis carried out the epitaxy of GaAs on Si by MOCVD systematically, and grew high quality GaAs/Si epilayer and InAs QDs on Si substrate. We used atomic force microscope, X-ray diffrac-tion, transmission electron microscopy, scanning electron microscope, photo-luminescence and etching pit devices to characterize the performance of the material. The main researches are as follows:(1) The two-step growth of GaAs/Si epitaxy was investigated. We opti-mized the temperature of the high temperature GaAs layer and the tempera-ture, thickness and material of the buffer layer. And the optimal condition of two-step growth is:the temperature of high temperature GaAs is685℃, the buffer layer is GaAs layer and the growth temperature is420℃, the thick-ness is70nm. The900nm epilayer of GaAs is grown with this growth con-dition and the ω-2θ XRD FWHM is412arcsec, the roughness is3.6nm in10μm×10μm scanning scope.(2) The three-step growth of GaAs/Si epitaxy was investigated. Combined with thermal cycle annealing, the EPD of the1.8μm epilayer grown by three-step growth reduced from108cm-2to3x106cm-2, the roughness reduced from2.4nm to1.8nm in10μm×10μm scanning scope. Three step growth improve the crystalline quality and surface morphology greatly and the surface roughness is one of the best one in the world.(3) The effect of inserting In0.15Ga0.85As/GaAs, Al0.9Ga0.1As/GaAs and GaAs0.85P0.15/GaAs superlattice dislocation filters based on three step growth was investigated. The crystalline quality get worse after inserting SLS. The best epilayer of crystalline quality is the one inserting GaAs0.85P0.15/GaAs su-perlattice layer. Compared with the epilayer without superlattice layer, the XRD FWHM increased from298arcsec to322arcsec and the RMS decreased from2.4nm to2.3nm in10μm×10μm scanning scope.(4) The growth of InAs QDs on Si substrate was investigated. To control the size and density of QDs by optimizing the growth conditions of QDs on Si substrate. Multiple QDs layers were grown on Si substrate and compared with multiple QDs layers on GaAs substate, the size and density of the multiple QDs on Si substrate reached the level of multiple QDs on GaAs substate, but the intensity of PL is much lower than QDs on GaAs and the intensity decreased about60%.(5) Inserting QDs dislocation filter in GaAs/Si epilayer was investigated. With the thickness of GaAs epilayer is3μm, three layer QDs dislocation filter improve the crystalline quality of GaAs/Si. Compared with the GaAs epilayer without dislocation filter, the EPD of the epilayer with dislocation filter reduced from108cm-2to3×106cm-2.