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US 5,569,611 AGranted
Method of manufacturing a bipolar transistor operating at low temperature
AssigneeNEC Corporation
InventorKiyotaka Imai
Life of this patent
Estimating the term…
Abstract
In a method of manufacturing a bipolar transistor, an oxide film pattern is formed on an epitaxial collector layer of a first conductive type which is formed on a buried layer of the first conductive type. A selectively-ion-implanted-collector (SIC) region is then formed in the collector layer, and after that, a base layer is grown on the SIC region with an inversely graded impurity distribution profile.
Claims9
A method of manufacturing a bipolar transistor, comprising the steps of:
- forming a collector region of a first impurity concentration;
- selectively forming an oxide film pattern on said collector region;
- forming an impurity-concentration-enhanced region in said collector region under said oxide film pattern;
- forming a base electrode on said collector region and a part of said oxide film pattern;
- removing said oxide film pattern;
- forming a base region at a portion formed by removing said oxide film pattern on surfaces of said collector region and said impurity-concentration-region, such that said base region has an inversely graded impurity distribution profile in which a concentration of impurity is high at the surfaces of said collector region and said impurity-concentration-region and low at an opposite surface of said collector region and said impurity-concentration-region and such that said base region is coupled to said base electrode region;
- and
- forming an emitter region in said base region.
5 more elements
A method of manufacturing a semiconductor device comprising the steps of:
- forming a collector region having a first impurity concentration;
- covering said collector region with an insulating film, impurities being selectively doped into said collector region through said insulating film to change a portion of said collector region to an impurity-concentration-enhanced portion thereby having a second impurity concentration higher than said first impurity concentration, a remaining portion of said collector region maintaining to have said first impurity concentration;
- growing, after said impurity-concentration-enhanced portion is formed and said insulating film is removed, a base region on surfaces of said impurity-concentration-enhanced portion and a part of said remaining portion of said collector region such that said base region has an inversely graded impurity distribution profile in which an impurity concentration of a bottom surface portion thereof facing with said impurity-concentration-enhanced portion is higher than an impurity concentration of a top surface portion opposite to said bottom surface portion thereof;
- and
- selectively forming an emitter region ion in said top surface portion of said base region.
2 more elements
A method of manufacturing a semiconductor device comprising the steps of:
- forming a collector region having a first impurity concentration;
- selectively doping impurities having a conductivity type of said collector region into said collector region to change a portion of said collector region to an impurity-concentration-enhanced portion thereby having a second impurity concentration higher than said first impurity concentration, a remaining portion of said collector region maintaining to have said first impurity concentration;
- growing, after said impurity-concentration-enhanced portion is formed, a base region on surfaces of said impurity-concentration-enhanced portion and a part of said remaining portion of said collector region such that said base region has an inversely graded impurity distribution profile in which an impurity concentration of a bottom surface portion thereof facing with said impurity-concentration-enhanced portion is higher than an impurity concentration of a top surface portion opposite to said bottom surface portion thereof;
- forming a first emitter electrode layer on said base region with no impurity or with slightly doped impurity;
- forming a second emitter electrode layer on said first emitter electrode layer with a concentration of impurity higher than that said first emitter electrode layer;
- and
- performing heat treatment to diffuse the impurity of said second emitter electrode layer into said base region such that an emitter region is formed.
4 more elements
A method of manufacturing a bipolar transistor, comprising the steps of:
- forming a collector region of a first impurity concentration;
- forming an impurity-concentration-enhanced region in said collector region, the impurity-concentration-enhanced region having a second impurity concentration higher than first impurity concentration;
- laminating first and second layers on surfaces of said collector region and said impurity-concentration-region, said first layer having a concentration higher than that of said second layer;
- performing heat treatment to form, from said first and second layers, a base region having an inversely graded impurity distribution profile such that a concentration peak is on the side of said collector region;
- forming a first emitter electrode layer on said first base region with no impurity or with slightly doped impurity;
- forming a second emitter electrode layer on said first emitter electrode layer with a concentration of impurity higher than that of said first emitter electrode layer;
- and
- performing heat treatment to diffuse the impurity of said second emitter electrode layer into said base region such that an emitter region is formed.
5 more elements
Dependencies are inferred from the claim text.