| 摘要 |
PURPOSE:To dispense with a forming process of a P<+> well through a resist mask so as to reduce man-hours by a method wherein an epitaxial wafer, in which a region corresponding to the P<+> well is buried, is employed. CONSTITUTION:A MOSFET of this design is a semiconductor board composed of a P<+> substrate 7, a buffer layer 6, a high resistive N<-> layer 5 comprising 5a and 5b, and a P<+> layer 12a buried between the 5a and 5b of the layer 5 which are epitaxially grown in lamination. The buried P<+> layer 12a is 10<17-18> atoms/cc in impurity concentration, extends into both the 5a and 5b of the N<-> layer 5 from the interface between the 5a and 5b as far as 5mum or so, and nearly 40mum in width, and the 5b of the N<-> layer 5 is about 10mum thick. As mentioned above, an epitaxial wafer is provided with the buried P<+> layer 12a which is to be a P<+> well, so that a resist film used for the formation of the P<+> well can be dispensed with and consequently man-hours can be reduced. |
