| 摘要 |
PURPOSE:To reduce a feedback capacitance through the self-alignment of gate portion and source and drain by doping impurity into the source and drain regions of MOS. CONSTITUTION:An MOS provides the structure that the first and second regions 21, 22 of the second semiconductor layer 19 are formed as the source and drain regions of MOS, the region 20 in high specific resistance consisting of a part of the semiconductor layer 19 is formed as the channel region, the gate insulating layer 17 is formed bridging over the regions 21, 22, and the region 13 consisting of a part of the first semiconductor layer 12 is formed thereunder as the gate electrode. In the drain region 22 of such MOS, static capacitances are formed between the insulating layers 18, 24 and regions 14, 26 of the first and third semiconductor layers 12, 25. The channel forming region 20 and source region 21 are electrically coupled. Since the oxide gate insulating layer 17 is formed by thermally oxidating the surface of first semiconductor layer 12 and polycrystalline silicon layer, a very stable MOS transistor with large capacitance Qss and small fluctuation can be obtained. |
