| Summary: | 碩士 === 明新科技大學 === 化學工程研究所 === 95 === Recently, the applications of relaxed SiGe layers in the silicon-based electronics and photonic devices attract many attentions. The high carrier mobility of silicon channel through the adjustable lattice constant, designed energy band and defect engineering can be utilized as the start material for high-speed electronics and photonic devices. The conventional relaxed SiGe buffer layer with thick layer and rough surface. Such a structure resulted in the device with thick thickness and high cost, which suffer deterioration later lithography process、and heat-up problem. In this thesis a new buffer with highly relaxed and thin relaxed SiGe layer is proposed. In this thesis, we studied thin relaxed Si1-xGex films by gas type ion implantation. There two types of structures for the samples used in our work. One was a 200-nm-thick SiGe with Ge content of 20% grown on Si wafer directly, the other one was Si0.8Ge0.2 film grown on the substrate consisting of Si/Si:B/Si substrate. H+ and He+ ions implant atom with dose of 2×1016 cm-2 were used as the ion source. Software simulator (TRIM 98) was used to design the depth of ion implantation with 100 nm beneath the interface of SiGe/Si substrate. After appropriately subsequental annealing, the relaxation (70%) of Si0.8Ge0.2 on Si/Si:B/Si is higher than that without buried B layer. Meanwhile, the microwave was also applied to enhance the relaxation of Si0.8Ge0.2/Si samples. The samples were put into the 1M sodium chloride solution, followed by subsequent annealing with appropriate power and time provided by microwave. Compared to the samples without microwave treatment, microwave processing enhanced the relaxation of SiGe thin films. The He＋implanted samples were treated with microwave at 135℃ and power of 1000 W for 1 minute, followed by subsequently annealing at 600℃for 10 minute, increased degree of relaxation 23% more than SiGe without microwave treatment. We proposed that the microwave treatment can reduce the nucleation energy of the defect induced by ion implantation, and the nucleation rate of the micro-cavity increased. This results may enhance the emission of misfit dislocations and help the relaxation in the SiGe thin films. By the research in this thesis, thin and relaxed SiGe can be achieved and serves as the potential candidate of starting materials for the strain-Si devices, III-V photonic devices, and solar cells.
Keywords：relaxed；SiGe thin film；microwave；defect engineering
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