| 摘要 |
PURPOSE:To separate an element and improve its reliability by providing a layer of higher concentration than a semiconductor element substrate and a layer of lower concentration than the former but of higher concentration than the substrate each at the lower part of a field insulation layer and a part overlapping a part of the region of a semiconductor element at the periphery. CONSTITUTION:A semiconductor element is formed on one main surface of P type semiconductor substrate 21 and field insulation films 22-24 are formed on the peripheral region of a region where the said semiconductor element is formed. Then P<++> layers 25, 26 of higher concentration than the substrate 21 are provided at the lower part of the insulation films 22-24. In addition, highly concentrated layer, 28, 29 which are of the same concentraton as or higher concentration than the substrate 21 formed at a part overlapping a part of the region of a semiconductor element at the periphery of the insulation films 22-24, are provided. Following this procedure, field films 30-32 are formed with gate electrodes 331, 332.... At the same time, N type layers 34, 34... are formed and electrodes are wired by means of wiring patterning to complete a semiconductor device. Thus it is possible to control the gate threshold value voltage of a field parasitic MOS transistor and the voltage withstanding capacity of PN seamed part and consequently separate an element and improve its reliability. |
