| 摘要 |
PURPOSE:To simplify a preparation process of transistors and to improve an integrated circuit grade by a method wherein a stable negative charge is produced by applying aluminum ion to a silicon dioxide film and a channel cut is performed by means of this negative charge. CONSTITUTION:A field oxidation is performed to the surface of a p type silicon semiconductor substrate and an aluminum ion is applied to the formed field oxide film 5. And thereafter, in order to expose a transistor forming area, an oxide film 5 is selectively removed and a gate oxide film 6 is formed, etc., to form an n channel MOS transistor. At this time, an aluminum ion doped in the oxide film 5 is substituted by silicon of the oxide film through an activation processing to form an energy level to trap an electron. As a result, the oxide film 5 comes into a state having a negative charge, and the surface part of the substrate 1 directly under the oxide film 5 is channel cut, thus, the MOS transistor being separated. |
