Bicmos devices with a self-aligned emitter and methods of fabricating such bicmos devices

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

• forming a base region on a substrate and overlying a collector defined in the substrate;
• forming an oxide layer over the base region;
• forming a temporary emitter over the base region and the oxide layer;
• forming spacers on the sidewalls of the temporary emitter;
• after forming the temporary emitter and spacers, thickening the oxide layer using an oxidation process wherein a growth rate in the oxide layer in areas not covered by the temporary emitter and the spacers is greater than that in areas covered by the temporary emitter and the spacers;
• removing the temporary emitter after growing the oxide;
• thinning the oxide layer, after removing the temporary emitter, to expose a base-emitter junction on a top surface of the base region and between the spacers, wherein the oxide layer continues to overlay the base region in the areas not covered by the temporary emitter after the base-emitter junction is exposed;
• and
• forming an emitter over the exposed base-emitter junction and between the spacers.