Study of basic technology for System-on-Glass

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We have speculated that dominant origin of small grains for the conventional excimer-laser annealing. (ELA) of Si thin-films is of collision of grain that start growing uniformly over the Si thin-films at the same time. We have developed a novel ELA method named as "Gradient method" that can grow large grains by solving an above-mentioned collision problem. Furthermore,. we have developed an improved method named "Phase-Modulated ELA method", to control well the light intensity distribution, by using interference effects of laser light. Grown grains was 100 times as large as the conventional ones, and repeatability was improved dramatically. And relations have been examined experimentally between grain size and light intensity distribution, average light intensity, sample temperature, surface passivation layer and so on. Mask design methodology, conditions of optical system for large grain growth and practical method using projection concepts are also investigated. Another lateral grow … More th technology has been invented where uniform excimer-laser light irradiates the sample of Si disk formed on the light absorption layer. Large grains can be grown by lateral diffusion of heat from the light absorption layer outside the Si disk.The fact that we can grow large grains at the pre-designed position means that we can make grain boundary at the pre-designed position. Based on this fact we have proposed a novel thin-film transistor structure where only one grain boundary is running at the center of the channel. Since the high field drain region exists in a single grain of good crystallinity, leakage is expected low. Since carriers cross only one the potential barrier formed at grain boundary, the field effect mobility is expected high. Grain boundary at the center of the channel can effectively kill holes by recombination, which results in a few kink effects. As a results superior performances are expected in these devices. We have fabricated this device by using PMELA method, and verified their superior performance. Less