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. 14, 1995
Filed:
Mar. 15, 1994
Ikunori Takata, Fukuoka, JP;
Toshiaki Hikichi, Fukuoka, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A Darlington transistor having improved comprehensive electric characteristic and a bipolar transistor having improved high voltage characteristic are obtained. A collector resistivity .rho.N.sup.- (F) of a collector high resistivity layer (11) in a front stage side transistor chip (TF) is set to 80 5/8cm and its collector film thickness tN.sup.- (F) is set to 120 .mu.m, and a collector resistivity .rho.N.sup.- (R) of a collector high resistivity layer (13) in a rear stage side transistor chip (TR) is set to 45 .OMEGA.cm and its collector film thickness tN.sup.- (R) is set to 160 .mu.m. Since .rho.N.sup.- (F)>.rho.N.sup.- (R) and tN.sup.- (F)<tN.sup.- (R) are satisfied, a Darlington transistor having a good comprehensive electric characteristic can be obtained, and also, since .rho.N.sup.- (R)/tN.sup.- (R)<0.6 is satisfied, a bipolar transistor having a good high voltage characteristic can be obtained (FIG. 8).