Investigation Of Novel Thin Films Transferred To Silicon Substrate

Current integrated circuit (IC) designs are quickly approaching their physical limits asnano-scale devices era looms. Novel technology, including silicon-on-insulator (SOI),Germanium-on-insulator (GOI), Germanium-silicon and Strained silicon, can providesome of the solutions in the sub-100-nm technology node.Under the above backgrounds, the works in this thesis focus on:(1) SOI structureobtained using N⁺ plasma activation and Smart-cut technology with low-temperatureprocess, and the quality of top silicon layer has been investigated. (2) High-speedsemiconductor materials GOI have been prepared and characterized. (3) LiTaO₃ materialsintegrated on silicon substrate using Smart-cut technology and eutectic bonding technologyhave been investigated, respectively.(1) The relationship between the annealing temperature and the bonding strength of Siand SiO₂ has been investigated. The bonding wafers were prepared with Silicon wafer andSilicon dioxide wafer using N⁺ plasma activated treatment. The research leads to two keyfindings. First, the bonding strength increases dramatically with the annealing temperatureranging from 100℃to 300℃. When the annealing temperature above 300℃, thebonding strength increases gradually and slowly with the annealing temperature increasing.The bonding strength of samples annealed at 300℃for 1 hour with plasma activation iscomparable to that of samples annealed at 1100℃for 1 hour without plasma activation.Second, Top silicon layer with low defect density (2×10⁴/cm²) has been obtained afterannealing at 500℃in N₂ atmosphere for 1 hour. (2) Germanium-on-insulator (GOI) materials have been fabricated successfully usingmodified smart-cut technology, which includes moderate H⁺ dose implantation, specialcleaning process of Ge wafer, low temperature wafer bonding and subsequent thermaltreatment. The surface morphology of hydrogen implanted into Ge wafers has beeninvestigated. Different from that of hydrogen implanted Si wafer, no obvious blisters wereobserved, however, the whole top Ge layer in chipped shape departed from substrate.Scanning electron microscope (SEM), atomic force microscope (AFM) and four-crystalX-ray diffraction have been used to characterize the microstructure of GOI materials. Theresults demonstrate that the defects of top Ge layer can be improved apparently afterannealing at 400℃for 12 hours, and the interface between Ge and buried silicon dioxideis sharp and uniform.(3) Single crystalline LiTaO₃ thin films on silicon substrate have been achieved bywafer bonding and layer transfer technology, which has significant influence on theapplication of silicon-based optoelectronic integration technology. The influence ofhydrogen implantation parameters on the surface blister LiTaO₃ of has been investigated.Results indicate that the surface blister can be observed when using appropriateimplantation energy and annealing process. The Cross-sectional Transmission ElectronicMicroscopy (XTEM) and X-Ray Diffraction (XRD) results indicate that the LiTaO₃ thinfilms are single crystalline and have good structure quality. In addition, theLiTaO₃/Metal/Silicon structure with stable metal interface has been achieved successfullyusing eutectic bonding technology.