| 摘要 |
PURPOSE:To improve the radius of curvature of the P-N junction for the subject semiconductor device by a method wherein a Ga or Al high density region is formed as a source of diffusion on the polycrystalline silicon layer formed on a silicon substrate through the intermediary of a silicon oxide film. CONSTITUTION:An SiO2 layer 2 of approximately 5,000Angstrom is formed on the main surface of the silicon substrate 1, and a polycrystalline silicon layer 11 of about 3,000Angstrom is formed on the layer 2. Then, a photoresist layer is formed on the layer 11, and a high density impurity region 11' is formed by ion-implantation of Al or Ga. After the photoresist layer has been removed, a thermal diffusion is performed using the high density impurity region 11' as the source of diffusion, and a P type diffusion region 13 is formed. As the diffusion is performed from the high density diffusion region through the SiO2 layer 2 of a high diffusion speed, the radius of curvature of the P-N junction 4 in the silicon substrate is increased and high withstand voltage can be obtained. |
