摘要 |
An SOI substrate is comprised of a support substrate, a buried insulating layer and a semiconductor layer. A 1poly-type memory cell has a pair of source/drain regions, a floating gate electrode layer, and a control gate impurity diffusion region. An isolation insulating layer extends from a surface of the semiconductor layer to reach the buried insulating layer while surrounding the periphery of the control gate impurity diffusion region thereby to separate a region in which the source/drain regions are formed and the control gate impurity diffusion region from each other. Therefore, a nonvolatile semiconductor can be obtained which can prevent a parasitic bipolar operation and is suitable for higher integration.
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