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:
May. 05, 1987
Filed:
Apr. 23, 1982
Takashi Mimura, Machida, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
The present invention is an improvement in a normally off-type high electron mobility transistor (HEMT) having a first single crystalline semiconductor layer, such as an undoped GaAs layer, and a second single crystalline semiconductor layer, such as an N-doped AlGaAs layer, having an electron affinity different from that of the first single crystalline semiconductor layer. A heterojunction is formed between the first and second single crystalline semiconductor layers. An electron-storing layer is formed adjacent to the heterojunctions serving as a conduction channel having a quasi two-dimensional electron gas. The concentration of electron gas is controlled by a gate electrode. An additional semiconductor layer, such as an N-doped GaAs layer, is formed at a portion of the second single crystalline layer in the area adjacent to the gate electrode. The additional semiconductor layer can generate the quasi two-dimensional electron gas even when no such gas is generated under the crystal parameter of the first and second single crystalline semiconductor layers. This generation of the quasi two-dimensional electron gas ensures that the HEMT has good reproducibility in respect to normally off-type operation.