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. 25, 2004
Filed:
Sep. 17, 2001
Institut fuer Halbleiterphysik Frankfurt (Oder) GmbH, Frankfurt, DE;
Abstract
The aim of the invention is to provide for a bipolar transistor and a method for producing the same. Said bipolar transistor should have minimal base-emitter capacities and very good high frequency characteristics. The static characteristics, especially the base current ideality and the low frequency noise, of a bipolar transistor with weakly doped cap layer ( ) should not significantly deteriorate and process complexity should not increase. According to the invention, the problem is solved by inserting a special doping profile in a cap layer ( ) (cap doping) which has been produced epitaxially. A minimal base emitter capacity and very good high frequency characteristics can be obtained by means of said doping profile. At the same time, the efficiency of the generation/recombination active boundary surface between the cap layer ( ) and the isolator ( ) in the polysilicon overlapping area in the relevant working area of the transistor is reduced and the base current ideality is improved. The section at the base side in the cap layer ( ) has a preferred thickness of between 20 nm and 70 nm and is only doped weakly, preferably less than 5·10 cm . Said section is crucial for the good high frequency characteristics.