Compound semiconductor device including AIN layer of controlled skewness
AssigneesFujitsu Limited, Hitachi Cable, Ltd.
InventorsKenji Imanishi, Toshihide Kikkawa, Takeshi Tanaka, Yoshihiko Moriya, Yohei Otoki
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Abstract
A semiconductor epitaxial substrate includes: a single crystal substrate; an AlN layer epitaxially grown on the single crystal substrate; and a nitride semiconductor layer epitaxially grown on the AlN layer, wherein an interface between the AlN layer and nitride semiconductor layer has a larger roughness than an interface between the single crystal substrate and AlN layer, and a skewness of the upper surface of the AlN layer is positive.
Claims5
A semiconductor epitaxial substrate comprising:
- a single crystal substrate;
- an AlN layer epitaxially grown on said single crystal substrate;
- a nitride semiconductor layer epitaxially grown on said AlN layer;
- a first device layer of nitride semiconductor epitaxially grown on said nitride semiconductor layer;
- and
- a second device layer of nitride semiconductor epitaxially grown on said first device layer,
- wherein an interface between said AlN layer and said nitride semiconductor layer has a larger roughness than an interface between said single crystal substrate and said AlN layer,
- wherein a skewness Rsk of an upper surface of said AlN layer is positive,
- wherein said first device layer is a channel layer, said second device layer is a carrier supply layer, and said nitride semiconductor layer has a higher resistivity than said first device layer, and
- wherein said single crystal substrate is SiC.
A manufacture method for a semiconductor epitaxial layer comprising:
- epitaxially growing an AlN layer on a single crystal substrate;
- and
- epitaxially growing a nitride semiconductor layer on said AlN layer,
- wherein growth conditions for said AlN layer are set in such a manner that an interface between said AlN layer and said nitride semiconductor layer has a larger roughness than an interface between said single crystal substrate and said AlN layer,
- wherein the growth conditions for said AlN layer include a growth temperature of 1100° C. to 1200° C. and a V/III ratio larger than 500,
- wherein said nitride semiconductor layer is an AlxGa1-xN (where 0.0<x≦0.1) layer having a thickness in a range of 10 nm to 200 nm, or a GaN layer having a thickness in a range of 10 nm to 200 nm, said GaN layer being doped with Fe at a concentration in a range of 1×1017cm−3 to 1×1019cm−3, and
- wherein a skewness Rsk of an upper surface of said AlN layer is positive.
Dependencies are inferred from the claim text.