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US 9,312,341 B2Granted
Compound semiconductor device, power source device and high frequency amplifier and method for manufacturing the same
AssigneeFujitsu Limited
InventorsTetsuro Ishiguro, Norikazu Nakamura
Life of this patent
Estimating the term…
Abstract
A compound semiconductor device includes: a substrate; and a compound semiconductor lamination structure formed over the substrate, the compound semiconductor lamination structure including a buffer layer containing an impurity, and an active layer formed over the buffer layer.
Claims11
A compound semiconductor device comprising:
- a substrate;
- and
- a compound semiconductor lamination structure formed over the substrate, the compound semiconductor lamination structure including
- a first buffer layer not containing an impurity,
- a second buffer layer formed over the first buffer layer and containing an impurity,
- a third buffer layer formed over the second buffer layer and not containing an impurity, and
- an active layer formed over the third buffer layer,
- wherein the third buffer layer has the same composition as that of the active layer, has a high ratio of lateral overgrowth as compared to that of the active layer.
5 more elements
A method for manufacturing a compound semiconductor device, the method comprising:
- forming a first buffer layer that does not contain an impurity;
- forming a second buffer layer over the first buffer layer, the second buffer layer contains an impurity;
- forming a third buffer layer over the second buffer layer, the third buffer layer does not contain an impurity;
- and
- forming an active layer formed over the third buffer layer,
- wherein the third buffer layer has the same composition as that of the active layer, has a high ratio of lateral overgrowth as compared to that of the active layer.
3 more elements
A power source device comprising:
- a high-voltage circuit including
- a transistor including
- a substrate, and
- a compound semiconductor lamination structure formed over the substrate, the compound semiconductor lamination structure including
- a first buffer layer not containing an impurity,
- a second buffer layer formed over the first buffer layer and containing an impurity,
- a third buffer layer formed over the second buffer layer and not containing an impurity, and
- an active layer formed over the third buffer layer;
- a low-voltage circuit;
- and
- a transformer formed between the high-voltage circuit and the low-voltage circuit,
- wherein the third buffer layer has the same composition as that of the active layer, has a high ratio of lateral overgrowth as compared to that of the active layer.
9 more elements
A high frequency amplifier which amplifies and sends an input high frequency voltage, the amplifier comprising:
- a transistor including
- a substrate, and
- a compound semiconductor lamination structure formed over the substrate, the compound semiconductor lamination structure including
- a first buffer layer not containing an impurity,
- a second buffer layer formed over the first buffer layer and containing an impurity,
- a third buffer layer formed over the second buffer layer and not containing an impurity, and
- an active layer formed over the third buffer layer,
- wherein the third buffer layer has the same composition as that of the active layer, has a high ratio of lateral overgrowth as compared to that of the active layer.
5 more elements
Dependencies are inferred from the claim text.