Semiconductor device and method for manufacturing the same

A method of manufacturing semiconductor devices at a major surface of a semiconductor substrate, comprising:

• (a) forming a first oxide film on said major surface of said semiconductor substrate;
• (b) forming an anti-oxidation film on said first oxide film;
• (c) locally forming a first mask layer on said anti-oxidation film;
• (d) etching said anti-oxidation film by using said first mask layer as a mask, so as to form a patterned anti-oxidation film;
• (e) introducing impurities of a first type of conductivity into said major surface of said semiconductor substrate not covered with said first mask layer in a self-aligned manner with said first mask layer in order to form a first semiconductor region of said first type of conductivity;
• (f) oxidizing said major surface of said semiconductor substrate not covered with said anti-oxidation film, so as to form a second oxide film in a self-aligned manner with said patterned anti-oxidation film;
• (g) introducing impurities of a second type of conductivity into said major surface of said semiconductor substrate not covered with said second oxide film in a self-aligned manner with said second oxide film in order to form a second semiconductor region;
• (h) forming a further anti-oxidation film on said major surface of said semiconductor substrate;
• (i) locally forming a second mask layer on said further anti-oxidation film so as to expose a part of said major surface of said semiconductor substrate on said first and second semiconductor regions;
• (j) etching said further anti-oxidation film using said second mask layer as a mask, so as to form an etched further anti-oxidation film;
• (k) introducing impurities into said semiconductor substrate not covered with said etched further anti-oxidation film in a self-aligned manner with said second mask layer;
• (l) oxidizing said major surface of said semiconductor substrate in a self-aligned manner with said etched further anti-oxidation film, in order to form a field insulating film on said major surface of said semiconductor substrate not covered with said etched further anti-oxidation film;
• (m) removing said etched further anti-oxidation film;
• (n) forming a gate electrode on said first semiconductor region;
• and
• (o) introducing impurities of said second type of conductivity into said first semiconductor region, in order form a source or a drain region in a self-aligned manner with said gate electrode and said field insulating film.

A method of manufacturing semiconductor devices at a major surface of a semiconductor substrate, comprising the steps of:

• (a) forming an anti-oxidation film on said major surface of the semiconductor substrate;
• (b) covering said anti-oxidation film with a photoresist mask to cover a portion of said anti-oxidation film overlying a first selected surface area of said major surface, and to leave another portion of said anti-oxidation film, overlying a second selected surface area of said major surface, not covered by said photoresist mask;
• (c) introducing impurities of a first conductivity type into said second selected surface area thereby to form a first semiconductor region of said first conductivity type at said second selected surface area;
• (d) subjecting and semiconductor substrate, which is covered by said portion of said anti-oxidation film but not covered by said another portion of said anti-oxidation film, said another portion having been removed by etching away said another portion of said anti-oxidation film not covered by said photoresist mask, to an oxidation treatment, thereby to form an oxide film at said second selected surface area;
• (e) introducing impurities of a second type of conductivity, opposite to said first conductivity type, into said first selected surface area using said oxide film as a mask, thereby to form a second semiconductor region of said second conductivity type at said first selected surface area;
• (f) forming a further anti-oxidation film on said major surface of said semiconductor substrate;
• (g) locally forming a second mask layer on said further anti-oxidation film so as to expose a part of said major surface of said semiconductor substrate on said first and second semiconductor regions;
• (h) etching said further anti-oxidation film using said second mask layer as a mask, so as to form an etched further anti-oxidation film;
• (i) introducing impurities into said main surface of said semiconductor substrate in a self-aligned manner with said second mask layer;
• (j) forming a field insulating film on said major surface of said semiconductor substrate not covered with said etched further anti-oxidation film, in a self-aligned manner with said etched further anti-oxidation film;
• (k) forming a gate electrode on said first semiconductor region;
• and
• (l) introducing impurities of said second conductivity type into said first semiconductor region, in order to form a source or a drain region in a self-aligned manner with said gate electrode and said field insulating film.