| 摘要 |
PURPOSE:To reduce further the occupying area of the surface of a semiconductor substrate by a method wherein an impurity layer and a semiconductor layer whose conductivity type is opposite to that of the impurity layer is formed on the surface of a semiconductor substrate and a conductive film which is to be a gate is provided on the inside surface of a recess which reaches the impurity layer on the semiconductor substrate with a thin insulating film in between. CONSTITUTION:After an impurity layer 5 is formed on the surface of a semiconductor substrate 1, a semiconductor layer 10 whose conductivity type is opposite to that of the impurity layer is formed by an epitaxial method or an ion implantation method. A recess 10a which reaches the impurity layer 5 through the semiconductor layer 10 is formed vertically to the semiconductor substrate 1. After a thin insulating film 3 is formed on the inside surface of the recess 10a and 1st conductive film 4 is formed on it, an impurity layer 6 whose conductivity type is the same as that of the impurity layer 5 is formed by using the 1st conductive film 4 as a mask. A source region and a drain region are formed in layer forms which are separated vertically from each other and a gate electrode is formed vertically to the semiconductor substrate. Therefore, the occupied area can be reduced compared with a conventional MOS transistor.
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