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AssigneeNEC Corporation
InventorYasunobu Nashimoto
Estimating the term…
A field effect transistor comprises a current channel layer formed on an InP substrate through a buffer layer and formed of InGaAs having a lattice constant in match with that of InP, and a source electrode and a drain electrode formed on the current channel layer separately from each other and in ohmic contact with the current channel layer. An insulator layer is formed on the current channel layer between the source electrode and the drain electrode, and a gate electrode is formed on the insulator layer. The insulator layer being composed of a superlattice layer formed of alternately stacked undoped InAs thin films and undoped AlAs thin films. A ratio t.sub.1 /t.sub.2 of the thickness t.sub.1 of each one InAs thin film and the thickness t.sub.2 of one AlAs thin film adjacent to the each one InAs thin film is gradually reduced toward to an upper surface of the superlattice layer.
A field effect transistor comprising an InGaAs current channel layer, a source electrode and a drain electrode formed on said current channel layer separately from each other and in ohmic contact with said current channel layer, an insulator layer formed above and in contact with said current channel layer between said source electrode and said drain electrode, and a gate electrode formed above and in contact with said insulator layer, said insulator layer being composed of a superlattice layer formed of alternately stacked undoped InAs thin films and undoped AlAs thin films, a ratio t.sub.1 /t.sub.2 of the thickness t.sub.1 of each one InAs thin film and the thickness t.sub.2 of one AlAs thin film adjacent to said each one InAs thin film being gradually reduced toward an upper surface of said superlattice layer.
A field effect transistor comprising an In.sub.0.53 Ga.sub.0.47 As current channel layer, a source electrode and a drain electrode formed on said current channel layer separately from each other and in ohmic contact with said current channel layer, an insulator layer formed above and in contact with said current channel layer between said source electrode and said drain electrode, and a gate electrode formed above and in contact with said insulator layer, said insulator layer being composed of a superlattice layer formed of alternately stacked undoped InAs thin films and undoped AlAs thin films, a ratio t.sub.1 /t.sub.2 of the thickness t.sub.1 of each one InAs thin film and the thickness t.sub.2 of one AlAs thin film adjacent to said each one InAs thin film being gradually reduced toward an upper surface of said superlattice layer in such a manner that a pair of adjacent thin films which consists of one InAs thin film and one AlAs thin film and is adjacent to said current channel layer has said ratio t.sub.1 /t.sub.2 of thickness equal to about 1.08, and a pair of adjacent thin films which consists of one InAs thin film and one AlAs thin film and is adjacent to said gate electrode has said ratio t.sub.1 /t.sub.2 of thickness substantially equal to 0.0064.
Dependencies are inferred from the claim text.