| 摘要 |
PURPOSE:To enlarge dielectric strength between a drain region and a gate region, to reduce floating capacity between electrodes, and to enable to execute surely high speed action of a semiconducor device by a method wherein a thick insulating film (silicon oxide film) is buried deep between the gate region and the drain region at each semiconductor element. CONSTITUTION:An oxidation treatment is performed at a low temperature to the surface of a layer 23 to obtain a silicon oxide layer 28. Because amorphous silicon is oxidized high speedily at a low temperature as compared with single crystal silicon, the remaining amorphous silicon part is oxidized thick, and the single crystal part is oxidized thin. A nitride film 19 is covered on the silicon oxide layer 28 excluding the upper sides of gate regions, boron, for example, is diffused through the windows of the nitride film 29 thereof to form a signal storing gate region 30 and a separated gate region 31 of p<+> type and having the desired depths. The nitride film 29 is removed, a photo resist having a window between the thick parts of the silicon oxide layer 28 is covered thereon, and ions of phosphorus, etc., are implanted through the window thereof to form an n<+> type drain region 32. Openings are formed according to etching, for example, in the silicon oxide layer 28, and an electrode 33 for the signal storing region 30, an electrode 34 for the separated gate region 31 and an electrode 35 for the drain region 32 are provided. |
