Patent ID: 6235601
Filing Date: 2001-05-22
Classification: H01L,Y10S

Abstract:
A method of manufacturing a vertical, self-aligned bipolar transistor, the method comprising the steps of:a) providing a substrate and forming a first layer of a first conductivity type adjacent the substrate, the first layer having a surface;b) forming a stack of layers over the surface of the first layer, the stack of layers including a polysilicon layer disposed on the surface of the first layer and doped with a dopant of a second conductivity type, a barrier layer, a silicide layer and an oxide layer, the polysilicon layer being disposed on the surface of the collector layer, the barrier layer being disposed on the polysilicon layer, the silicide layer being disposed on the barrier layer and the oxide layer being disposed on the barrier layer;c) patterning and etching the stack of layers so as to expose at the surface of the first layer an active area having an interface with the stack of layers, the layers of the stack having edges substantially vertically aligned at said interface defining the active area;d) oxidizing the active area and the polysilicon layer adjacent the active area to form (i) a screen oxide layer from the first layer in the exposed active area and (ii) a lateral oxide in the polysilicon layer in a region contiguous with the active area, a non-oxidized region of the polysilicon layer remaining adjacent to the lateral oxide;e) forming an implanted base by implanting a dopant of the second conductivity type through the screen oxide layer, the lateral oxide of the polysilicon layer providing a lateral separation between the non-oxidized region of the polysilicon layer and the implanted base;f) selectively driving by diffusion the dopant of the second conductivity type of the polysilicon layer into the first layer to form a base contact;g) forming oxide spacers in the active area on the screen oxide layer and contiguous with the edges of the layers of the stack of layers; andh) forming an emitter in the active area on the base by depositing dopant of a first conductivity type in the active area.