The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 28, 1991
Filed:
Jul. 05, 1990
Robert L Virkus, Garland, TX (US);
David B Spratt, Plano, TX (US);
Eldon J Zorinsky, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A method for forming a self-aligned horizontal transistor includes the step of first defining a narrow base contact on an isolated N-tank (10) to define a first reference edge (41). A layer of sidewall oxide (40) is then disposed on the vertical wall of the base contact (34) to define a second reference edge (42). An emitter well (44) and a collector well (46) are then defined on either side of the contact with the vertical wall of the emitter well (44) aligned with the reference edge (42). A dopant material is then disposed adjacent the reference edge (42) and the dopant diffused into the substrate from a lateral direction to form a P-type base region (58) with a graded impurity profile. N-doped regions (64) and (66) are then formed in the emitter and collector wells to form the emitter and collector of the transistor.