| 摘要 |
A process allowing so-called indirect-heating SOI methodology to selectively transform predefined regions of a semiconductor film formed on an insulating substrate into grain-boundary-free regions. In an indirect-heating SOI, a semiconductor film which is recrystallized to be grain-boundary free is heated above its melting point by the heat generated in an energy-absorbing layer formed thereon. In the present invention, a layer having a relatively smaller thermal conductivity, such as SiO2 layer, is provided between the semiconductor film to be recrystallized and the energy-absorbing layer, both having larger thermal conductivities. The smaller-thermal-conductivity layer, functioning as a thermal-resistance, has selectively increased thickness at the portions thereof corresponding to the predefined regions transformed to be grain-boundary free in the semiconductor film. In each of the predefined regions, a desired temperature distribution profile, that is, the lowest at the center of the region and becoming higher toward the periphery of the region, is established, when the energy-absorbing layer is irradiated with a beam of radiant energy sufficient to melt the semiconductor film. Thus, the semiconductor film can be recrystallized to be grain-boundary-free single crystalline in each predefined region.
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