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:
Jul. 25, 2000
Filed:
Apr. 07, 1998
Shigeki Sawada, Kyoto, JP;
Matsushita Electronics Corporation, Osaka, JP;
Abstract
In a Bi-CMOS integrated circuit device, to reduce a collector-substrate junction capacitance in an NPN transistor and to reduce the step of forming an anti-punch-through layer of the N-channel MOS transistor. Using as a mask a resist pattern having windows made on an element isolation LOCOS film 113a, 113c and P-type well layer 106, impurities are ion-implanted to form a channel stopper layer 115a, 115b for element isolation of a NPN transistor and an anti-punch-through layer 115c for a N-channel MOS transistor. Thus, a sufficient element isolation withstand voltage can be assured while avoiding an increase in the collector-substrate capacitance of the NPN transistor which is due to the transverse diffusion of the channel stopper layer when an epitaxial layer, well layer and LOCOS film are formed. In addition, without increasing the number of steps, the drain-source withstand voltage of the N-channel type MOS transistor and the short channel durability can be improved.