| 摘要 |
PURPOSE:To prevent the injection of electron into a gate oxide film by a method wherein a drain region is buried below the surface of a semiconductor region. CONSTITUTION:In the MOSFET consisting of a source region 30, a drain region 31, a gate oxide film 34 and a gate electrode 36, the region 31 is buried under the surface of an Si substrate 32. Accordingly, as the hot electron, which was generated in the vicinity 33 of the boundary of a p layer and an n layer, loses its energy due to the phonon scattering with a lattice before it reaches an oxide film 34 and said hot electron is unable to pass the potential barrier of the oxide film 34, the fluctuation of threshold voltage can be prevented. Also, according to this constitution, the fundamental operation of the transistor is not impaired. As a result, the deterioration of reliability of the transistor caused by the implantation of hot electron into the oxide film 34 can be effectively improved without lowering the integration. |
