Method for making a bipolar transistor and capacitors using doped polycrystalline silicon or metal silicide

Claim 1

A method for manufacturing a semiconductor device, comprising the steps of: forming a semiconductor substrate of a first conductivity type having a first impurity region and a second impurity region of a second conductivity type; forming an oxide film on said semiconductor substrate; forming on said oxide film a silicon nitride film having a first opening above said first impurity region and a second opening above said second impurity region; forming a contact hole in said oxide film through said second opening; forming a conductive layer containing an impurity of the first conductivity type, and made of a material selected from the group consisting of polycrystalline silicon and metal silicide, on said silicon nitride film and exposed regions of said oxide film and said substrate; selectivity removing said conductive layer to leave a first portion on said oxide film and a second portion on said substrate, said first portion acting as a barrier layer for protecting said oxide film, and said second portion acting as an intermediate layer; forming a third impurity region of the first conductivity type in said second impurity region by diffusing the impurity of said second portion into said second impurity region; and forming metal electrodes connected to said barrier layer and said intermediate layer.

Claim 2

A method for manufacturing a semiconductor device, comprising the steps of: forming a semiconductor substrate of a first conductivity type having a first impurity region and a second impurity region of a second conductivity type; forming an oxide film on said semiconductor substrate; forming on said oxide film a silicon nitride film having a first opening above said first impurity region and a second opening above said second impurity region; forming a contact hole in said oxide film through said second opening; forming a conductive layer containing an impurity of the first conductivity type, and made of a material selected from the group consisting of polycrystalline silicon and metal silicide, on said silicon nitride film and exposed regions of said oxide film and said substrate; selectivity removing said conductive layer to leave a first portion on said oxide film and a second portion on said substrate, said first portion acting as a barrier layer for protecting said oxide film, and said second portion acting as an intermediate layer; forming a third impurity region of the first conductivity type in said second impurity region by diffusing the impurity of said second portion into said second impurity region; and forming metal electrodes connected to said barrier layer and said intermediate layer.