MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PURPOSE:To improve the controllability of thickness of polycrystalline silicon layer and gate oxide film while eliminating any leak current from the gate oxide film by a method wherein after forming a gate electrode on an oxide film by CVD process, a source region and a drain region are formed utilizing the gate electrode as a mask. CONSTITUTION:An oxide film 14 is formed on a thermal oxide film 13 by CVD process. A gate oxide film 30 is formed on a polycrystalline silicon layer 12 by laminating the thermal oxide film 13 and another oxide film thus formed. Firstly an impurity added polycrystalline silicon layer 15 is formed on the oxide film 14 by CVD process. Secondly the silicon layer 15, the oxide film 14 and the thermal oxide film 13 are etched to form the layer 15 after etching process into a gate electrode 16. Thirdly a silicon glass film 17 is formed by CVD process etc. Finally phosphorus contained in the silicate glass film 17 may be diffused in said polycrystalline layer 12 to form a source region 18 and a drain region 19 utilizing the gate electrode 16 as a mask for selective diffusion.