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:
Jun. 25, 1991
Filed:
Sep. 21, 1989
Keiichi Ohata, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
For improvement in a transit time of electrons, there is disclosed a heterojunction field effect transistor fabricated on a semi-insulating GaAs substrate, comprising a first layer overlying the semi-insulating substrate and formed of a high-purity GaAs, a second layer overlying the first layer and formed of an n-type AlGaAs which is smaller in electron affinity than the high-purity GaAs, a source region penetrating from the first layer into the second layer so as to be in contact with the active channel layer formed in the first layer and formed of an gallium-rich AlGaAs, a drain region, and a gate electrode formed on the second layer, an energy gap takes place between the source region and the first layer due to a lower edge of the conduction band thereof higher in energy level than that of the high-purity GaAs, thereby accelerating electrons supplied from the source region to the active channel layer.