| 摘要 |
PURPOSE:To provide a semiconductor device which can be manufactured minutely without increasing the process step number and in which parasitic resistance in a layer for making high voltage-resistant can be easily controlled, by forming an interface between a semiconductor substrate and a gate insulating film deeply than an impurity layer for making high voltage-resistant. CONSTITUTION:In a field effect semiconductor device, impurity layers 46, 48 are formed on a semiconductor substrate 41, an insulating film 49 is formed thereon, and then etching from the insulating film to the substrate is done selectively with normal PEP using a resist film 50, so that an impurity layer section for field and for making high voltage-resistant and a SDG region are separated individually. That is, leaving a fied oxidation film on the high voltage-resistant impurity layer 46 surrounding a drain, the remaining portions are etched away to the substrate deeply than the high ovltage-resistant impurity layer for the purpose of forming the SDG region. Thus, by self alignment to the gate and drain regions, a parasitic resistance in the high voltage-resistant impurity layer can be made. |
