| 摘要 |
PURPOSE:To form a vertical MOSFET having high speed switching characteristics by forming a P-well region and N<+> type region by double diffusion from the same diffusing window of polygonal shape that all edge angles become 150 deg. or larger. CONSTITUTION:A gate oxidized film 3, a gate electrode 5, a P-well region 8, a P<+> type contacting region 15, an N<+> type source region 16 are formed on a semiconductor substrate having an epitaxial layer 2 on the upper surface of a silicon wafer 1, thereby forming a vertical MOS transistor. In the diffusions of the regions 8, 15, 16, double diffusions are executed from the same diffusing window of polygonal shape that all edge angles are 150 deg. or larger. Thus, the lateral diffusing density become uniform irrespective of the corners and the sides of the window, thereby forming a vertical MOS transistor having low ON voltage and low ON resistance and high speed switching characteristics. |
