Method of forming a bilevel, self aligned, low base resistance semiconductor structure
AssigneeSGS-Thomson Microelectronics S.A.
InventorWilliam P. Imhauser
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Abstract
A semiconductor device is manufactured with precisely formed base and emitter regions. This is accomplished by arranging a plurality of insulator layer portions to form a plurality of windows. A dopant is then applied to the semiconductor device between the windows in order to accurately position emitter regions relative to base regions. In this manner a base of controlled dimensions can be formed. Thus the parasitic resistance of the base can be reduced and the figure of merit (emitter periphery/base area) can be increased.
Claims5
A method of manufacturing a vertically diffused semiconductor device, said method comprising the steps of:
- a) providing a semiconductor wafer which includes a surface region of a first conductivity type;
- b) providing an insulating layer over a portion of said surface region;
- c) introducing a dopant to a further portion of said surface region;
- d) covering selected areas of said further portion of said surface region, wherein each of said selected areas is covered with a respective one of a plurality of insulating layer portions;
- e) etching said surface region to remove still further portions of said surface region to create a plurality of recesses in said surface region wherein a portion of each of said insulating portions extends above a portion of a respective one of said plurality of recesses so that said plurality of insulating layer portions form a plurality of windows;
- f) introducing through said extending portion of each of said insulating portions and through said plurality of windows a first conductivity dopant to form a plurality of base regions in said surface region;
- and
- g) introducing a second conductivity dopant opposite in conductivity to said first conductivity dopant exclusively through said plurality of windows to form a plurality of emitter regions, each of said emitter regions positionally corresponding to a respective one of said plurality of windows and positionally aligned relative to a respective one of said plurality of base regions, in order to form a vertically diffused semiconductor device.
Dependencies are inferred from the claim text.