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. 11, 2000
Filed:
Jul. 16, 1998
Yasushi Amamiya, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A heterojunction bipolar transistor (HBT) has shortened electron transport time through collector region over wide range of biased conditions. The HBT is expected to exhibit enhanced high frequency characteristics. In operation under biased condition, a portion of an n-GaAs collector layer makes a depletion region. A p-GaAs base contact layer is in contact with side surface of the depletion region. Even if the collector layer remains in the n-type, the contour of band potential in conduction band of the collector depletion region is adjusted to a desired one by controlling electric potential of the base contact layer. As a result, the band potential with smooth slope is created in the collector depletion region, shortening transport time through the collector layer. The intrinsic portion of the collector layer is of the n-type so that occurrence of Kirk effect is suppressed, ensuring enhanced high frequency characteristics.