Self-aligned bipolar transistor manufacturing method
AssigneeSTMicroelectronics S.r.l.
InventorYvon Gris
Life of this patent
Estimating the term…
Abstract
The manufacturing of a bipolar transistor, including the steps of depositing a P-type polysilicon layer and an insulating layer on an N-type substrate; defining in said layers a base-emitter opening; performing a P-type doping and annealing to form a heavily-doped region partially extending under the periphery of the polysilicon layer; forming a spacer in an insulating material inside the opening; isotropically etching the silicon across a thickness greater than that of the heavily-doped region to form a recess; conformally forming by selective epitaxy a P-type silicon layer to form the transistor base layer; and depositing N-type heavily-doped polysilicon to form the transistor emitter.
Claims6
A method for manufacturing a bipolar transistor, including the steps of:
- defining an active area in a surface of a silicon layer of a first conductivity type;
- depositing a polysilicon layer doped of a second conductivity type and an insulating layer;
- defining in said layers a base-emitter opening;
- doping according to the second conductivity type and annealing to form a heavily-doped region partially extending under a periphery of the polysilicon layer;
- forming a spacer made of an insulating material inside the opening;
- isotropically etching the silicon across a depth greater than that of the heavily-doped region to form a recess;
- conformally forming, by selective epitaxy, a silicon layer of the second conductivity type to form the transistor base layer;
- and
- depositing polysilicon heavily-doped of the first conductivity type to form the transistor emitter.
Dependencies are inferred from the claim text.