Method of fabricating a semiconductor device having an insulating side wall

Claim 1

A method of producing a semiconductor device including a bipolar transistor, comprising the steps of: (a) forming a semiconductor layer of a first conductivity type for formulation into a base region on a substrate; (b) providing an insulating film of a width W1 on the semiconductor layer; (c) providing a conductive layer, for formulating into a base electrode, so that the conductive layer covers the insulating film on the semiconductor layer and contacts the semiconductor layer; (d) providing a nitride layer on the conductive layer; (e) removing partially the conductive layer and the nitride layer, for forming an opening having a width W2, which is smaller than the width W1 of the insulating film; (f) introducing a dopant into the opening for forming a semiconductor layer of a second conductivity type, for formulation into a emitter, within the semiconductor layer; (g) after said step (f), performing an oxidization for forming an oxide at a side wall and at a bottom wall of the opening; (h) etching for removing the oxide and the insulating film at the bottom of the opening, with the oxide remaining at the side wall; and (i) burying a conductor within the opening for forming an emitter electrode for contact to the semiconductor layer.

Claim 2

A method of producing a semiconductor device including a bipolar transistor, comprising the steps of: (a) forming a semiconductor layer of a first conductivity type for formulation into a base region on a substrate; (b) providing an insulating film of a width W1 on the semiconductor layer; (c) providing a conductive layer, for formulating into a base electrode, so that the conductive layer covers the insulating film on the semiconductor layer and contacts the semiconductor layer; (d) providing a nitride layer on the conductive layer; (e) removing partially the conductive layer and the nitride layer, for forming an opening having a width W2, which is smaller than the width W1 of the insulating film; (f) introducing a dopant into the opening for forming a semiconductor layer of a second conductivity type, for formulation into a emitter, within the semiconductor layer; (g) after said step (f), performing an oxidization for forming an oxide at a side wall and at a bottom wall of the opening; (h) etching for removing the oxide and the insulating film at the bottom of the opening, with the oxide remaining at the side wall; and (i) burying a conductor within the opening for forming an emitter electrode for contact to the semiconductor layer.