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:
Dec. 01, 1998
Filed:
Mar. 17, 1994
Fujitsu Limited, Kawasaki, JP;
Abstract
A semiconductor device includes a buffer layer of AlGaAs that contains oxygen with a concentration level in the approximate range of 8.times.10.sup.17 cm.sup.-3 to 6.times.10.sup.19 cm.sup.-3, and carbon with a concentration level in the approximate range of 2.times.10.sup.16 cm.sup.-3 to 2.times.10.sup.17 cm.sup.-3. A lattice constant of the AlGaAs buffer layer is larger than a lattice constant of the GaAs substrate so a lattice misfit of the AlGaAs layer with respect to the GaAs substrate is equal to or varies by no more than 2.times.10.sup.5 from a corresponding lattice misfit between an undoped AlGaAs crystal with respect to the GaAs substrate. Oxygen atoms occupy an interstitial site, creating a deep impurity level that suppresses side gate effect.