Method for manufacturing a semiconductor device including an impurity-doped silicon film
View Patent ↗A process for manufacturing a semiconductor device consecutively includes forming a recess in the surface region of a silicon substrate, forming a gate insulation film on the surface of the recess, depositing a silicon electrode film including an oxygen-mixed layer extending parallel to the surface of the recess, injecting impurities into silicon the electrode film 17 , and heat-treating the silicon electrode film to diffuse impurities.
1. A method for manufacturing a semiconductor device including a recessed-channel MOSFET, comprising:
forming a recess in a surface region of a semiconductor substrate, said recess having a plurality of surfaces;
forming a gate insulation film on said plurality of surfaces of said recess;
forming a silicon electrode on said gate insulation film by forming an oxygen-mixed layer on a first silicon electrode film, said oxygen-mixed layer being substantially parallel to each of said plurality of surfaces of said recess and being covered by a second silicon electrode film to fill said recess;
injecting impurities in said second silicon electrode film; and
heat-treating said first and second silicon electrode film to diffuse said impurities.
2. The method according to claim 1 , wherein a distance between said surface of said recess and said oxygen-mixed layer is equal to or less than half a minimum width of said recess.
3. The method according to claim 1 , wherein said impurities are of n-type.
4. The method according to claim 1 , wherein said impurities are of p-type.
5. The method according to claim 1 , wherein said heat-treating crystallizes said first silicon electrode film and said second silicon electrode film and forms a crystal grain interface, with said oxygen-mixed layer as a boundary.
6. The method according to claim 1 , wherein a thickness of said first silicon electrode film is equal to or less than half a minimum width of said recess.
7. The method according to claim 1 , wherein a thickness of said oxygen-mixed layer is formed by performing a thermal oxidation of a top surface of said first silicon electrode film.
8. The method according to claim 1 , wherein said first silicon electrode film, said oxygen-mixed layer and said second silicon electrode film constitute a silicon electrode.
9. The method according to claim 1 , wherein said first and said second silicon electrode films are formed in an amorphous state.