Semiconductor device and method for fabricating same

A method of fabricating a semiconductor device comprising the steps of:

• 1) forming a gate electrode on a first region of a semiconductor substrate having a first conductivity type with an intermediate gate oxide layer disposed therebetween and forming diffused layers having a second conductivity type different from said first conductivity type in a pair of second regions of the semiconductor substrate between which said first region is disposed;
• 2) forming a silicon dioxide film and a polycrystalline silicon film one after another on an upper surface and two side surfaces of said gate electrode and said pair of second regions of said substrate and forming a side wall on each of said side surfaces of said gate electrode by etching away parts of said polycrystalline silicon film other than parts thereof formed on said two side surfaces of said gate electrode;
• 3) forming an interlayer insulating film on said silicon dioxide film and said polycrystalline silicon film and forming a contact hole reaching one of said second regions of said substrate through said interlayer insulating film so as to expose a part of said side wall therein;
• and
• 4) oxidizing the exposed part of said side wall thereby forming a silicon dioxide film at a surface of the exposed part of said side wall.

A method of fabricating a semiconductor device comprising:

• providing a semiconductor substrate having a first conductivity type;
• forming a pair of spaced diffused layers having a second conductivity type different from said first conductivity type in surface portions of said semiconductor substrate;
• forming a gate electrode on a channel region between said pair of diffused layers in said semiconductor substrate with an intermediate gate oxide layer disposed therebetween;
• forming a silicon dioxide film layer to cover an upper surface and side surfaces of said gate electrode and surface portions of said substrate in which said pair of diffused layers are formed;
• forming a side wall made of polycrystalline silicon to cover said silicon dioxide film on each of the side surfaces of said gate electrode;
• forming an interlayer insulating film of silicon dioxide to cover said silicon dioxide film layer, said side wall and said substrate;
• forming a contact hole through said interlayer insulating film to reach one of said pair of diffused layers, so that a part of said side wall is exposed within said contact hole due to the etching selectivity ratio between said interlayer insulating film and said side wall;
• and
• oxidizing a surface of the exposed part of said side wall to form a silicon dioxide film thereon.