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:
Aug. 27, 2002
Filed:
Nov. 24, 2000
Ted Johansson, Djursholm, SE;
Hans Norström, Solna, SE;
Telefonaktiebolaget LM Ericsson (publ), Stockholm, SE;
Abstract
In the fabrication of a silicon bipolar transistor, a method for forming base regions and for opening an emitter window is provided. A silicon substrate is provided with suitable device isolation. A first base region is formed in or on top of the substrate. A thin layer of oxide is formed on the first base region. A layer of silicon is formed on top of the thin oxide layer, the silicon layer is to be a second base region. The silicon layer is ion implanted. A layer of a dielectric is formed on top of the silicon layer, the dielectric is to isolate base and emitter regions of the transistor. The obtained structure is patterned in order to define the emitter window. The structure inside the defined emitter window area is etched and through the dielectric and silicon layers, wherein the thin oxide layer is used as etch stop, thus forming the emitter window. The structure is subsequently heat treated and thus break up the oxide such that the first and second base regions will contact each other.