| 摘要 |
PURPOSE:To contrive the decrease of ON-resistance of a double diffused MOSFET in a cascode connection and to make the speed high by a method wherein a channel of J type FET is formed in drum shape by utilizing a transverse diffusion in a step region. CONSTITUTION:An N-epitaxal layer 2 is formed on an N<+> type Si substrate 1 and SiO2 7 is mounted to be etched. Then, the SiO2 7 is selectively mount also on the side surface of a convex 2' of the layer 2 and B-diffused to form P-layers 3, 3' and thereupon, parts 3a, 3'a are projected to the epitaxial layer. Thereafter, the P-layers are covered with SiO2 and opened a window to induce As and N type sources 4, 4' are formed in the layeres 3, 3'. The SiO2 on the side of the convex 2' is removed and a gate oxide film is formed to be attached with electrodes 5, 10. With this construction, since the ends of the gate 3, 3' can be thoroughly approached even by the shallow diffusion, the withstand is elevated, a P-N junction area is also decreased, a feedback capacity of an element is decreased and easily made high speed. In addition, the diffused layer is formed so shallow that the ion-resistance can thoroughly be decreased. |
