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:
Mar. 10, 1998
Filed:
May. 16, 1994
Atsuo Watanabe, Hitachiohta, JP;
Yoshiaki Yazawa, Hitachi, JP;
Atsushi Hiraishi, Hitachi, JP;
Masataka Minami, Hitachi, JP;
Takahiro Nagano, Hitachi, JP;
Takahide Ikeda, Tokorozawa, JP;
Naohiro Momma, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A semiconductor device has a well region formed in the surface of a substrate, and has functional portions such as MOSFET and bipolar transistor formed in the well region. The carrier concentration profile of the well region assumes the shape of a valley in the direction of depth thereof, and a minimum point thereof has a concentration of smaller than 5.times.10.sup.15 cm.sup.-3 and is located at a position within 1.6 .mu.m from the surface of the substrate. Preferably, the minimum point should have a concentration of greater than 5.times.10.sup.14 cm.sup.-3 but smaller than 5.times.10.sup.15 cm.sup.-3, and more preferably a concentration of greater than 1.times.10.sup.15 cm.sup.-3 but smaller than 5.times.10.sup.15 cm.sup.-3.