摘要 |
An object of one embodiment of the disclosed invention is to provide a semiconductor device having a novel structure in which stored data can be held even when power is not supplied and the number of times of writing is not limited. The semiconductor device is formed using an insulating layer formed over a supporting substrate and, over the insulating layer, a highly purified oxide semiconductor and single crystal silicon which is used as a sililcon on insulator (SOI). A transistor formed using a highly purified oxide semiconductor can hold data for a long time because leakage current thereof is extremely small. Further, by using an SOI substrate and utilizing features of thin single crystal silicon formed over an insulating layer, fully-depleted transistors can be formed; therefore, a semiconductor integrated circuit with high added values such as high integration, high-speed driving, and low power consumption can be obtained.
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