Semiconductor device and method of manufacturing semiconductor device wherein field oxide is protected from overetching

A method of manufacturing a semiconductor device, comprising:

• forming an oxidation proof layer including an aperture on a silicon substrate;
• forming a field oxide for device isolation in the aperture;
• depositing a polysilicon layer thicker than a thickness of said oxidation proof layer on said oxidation proof layer and said field oxide, said polysilicon layer being a selectively removable material capable of establishing a condition under which said oxidation proof layer is selectively removed;
• making said polysilicon layer residual on only a surface of said field oxide by removing a part of said polysilicon layer deposited during said depositing, until a surface of said oxidation proof layer is exposed;
• removing said oxidation proof layer;
• forming a gate of a transistor on a surface of said substrate;
• making an oxide layer on said residual polysilicon layer, said gate and said substrate;
• removing said oxide layer until a surface of said residual polysilicon layer is exposed and a side-wall of said oxide layer is formed on said gate;
• forming an insulating layer on the semiconductor device, said insulating layer having a contact hole formed therethough;
• and
• connecting a wire to said gate through said contact hole.

A method of manufacturing a semiconductor device comprising:

• forming an oxidation resisting layer with an aperture therein on a substrate;
• forming a field oxide within the aperture;
• depositing a protective layer on the oxidation resisting layer and the field oxide, the protective layer having a thickness greater than a thickness of the oxidation resisting layer;
• removing a portion of the protective layer deposited on the oxidation resisting layer to expose the oxidation resisting layer and so that a residual portion of the protective layer remains on the field oxide within the aperture,
• the protective layer and the field oxide comprising materials having respectively different removal rates;
• removing the oxidation resisting layer;
• forming a gate on a surface of an active region of the substrate;
• forming an oxide layer on the substrate, the gate and the protective layer;
• removing the oxide layer until a surface of the protective layer is exposed and side-walls of the oxide layer are formed on the gate;
• forming an insulating layer on the semiconductor device, the insulating layer having a contact hole formed therethrough;
• and
• connecting a wire to the gate through the contact hole,
• the protective layer being a material difference than the oxide layer.