Abstract: In a compound semiconductor epitaxial substrate used for a strain channel high electron mobility field effect transistor which comprises an InGaAs layer as a channel layer 9 and AlGaAs layers containing n-type impurities as electron supplying layers 6 and 12, the channel layer 9 has an electron mobility at room temperature of 8300 cm2/V·s or more by adjusting an In composition of the InGaAs layer composing the channel layer 9 to 0.25 or more and optimizing the In composition and the thickness of the channel layer 9. GaAs layers 8 and 10 having a thickness of 4 nm or more each may be laminated respectively in contact with a top surface and a bottom surface of the channel layer 9.

Abstract: A method for producing a compound semiconductor wafer used for production of HBT by vapor growth of a sub-collector layer, a collector layer, a base layer and an emitter layer in this turn on a compound semiconductor substrate using MOCVD method wherein the base layer is grown as a p-type compound semiconductor thin film layer containing at least one of Ga, Al and In as a Group III element and As as a Group V element under such growth conditions that the growth rate gives a growth determined by a Group V gas flow rate-feed.

Abstract: A compound semiconductor epitaxial substrate including a substrate, and a sub-collector layer, a collector layer, a base layer, an emitter layer and a contact layer(s) formed in this order on the substrate, the compound semiconductor epitaxial substrate having an oxygen-containing layer between the substrate and the sub-collector layer.

Abstract: A compound semiconductor epitaxial substrate having a pseudomorphic high electron mobility field effect transistor structure which comprises an InGaAs layer as a channel layer 9 and an InGaP layer containing n-type impurities as a front side electron supplying layer 12, wherein an electron mobility in the InGaAs layer at room temperature (300 K) has become 8000 cm2/V·s or more by growing an epitaxial substrate having a pseudomorphic HEMT structure with an In composition of the channel layer 9 increased. Front side spacer layers 10 and 11 between the channel layer 9 and the front side electron supplying layer 12 may also be InGaP layers.

Abstract: A compound semiconductor epitaxial substrate for use in a strain channel high electron mobility field effect transistor, comprising an InGaAs layer as a strain channel layer 6 and AlGaAs layers containing n-type impurities as back side and front side electron supplying layers 3 and 9, wherein an emission peak wavelength from the strain channel layer 6 at 77 K is set to 1030 nm or more by optimizing the In composition and the thickness of the strain channel layer 6.

Abstract: A method for producing a compound semiconductor wafer used for production of HBT by vapor growth of a sub-collector layer, a collector layer, a base layer and an emitter layer in this turn on a compound semiconductor substrate using MOCVD method wherein the base layer is grown as a p-type compound semiconductor thin film layer containing at least one of Ga, Al and In as a Group III element and As as a Group V element under such growth conditions that the growth rate gives a growth determined by a Group V gas flow rate-feed.

Abstract: A compound semiconductor epitaxial substrate including a substrate, and a sub-collector layer, a collector layer, a base layer, an emitter layer and a contact layer(s) formed in this order on the substrate, the compound semiconductor epitaxial substrate having an oxygen-containing layer between the substrate and the sub-collector layer.

Abstract: A compound semiconductor device comprising a hetero junction bipolar transistor including a compound semiconductor substrate, and a sub-collector layer, a collector layer, a base layer and an emitter layer formed in this order as thin crystalline layers on the compound semiconductor substrate by vapor phase deposition, wherein the base layer is a thin film of a p-type compound semiconductor doped with C and no peak of a type of bonding between H and C, C2-H, is detected in infrared absorption measurement at room temperature.