THICK PSEUDOMORPHIC NITRIDE EPITAXIAL LAYERS
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Abstract
In various embodiments, a semiconductor device includes an aluminum nitride single-crystal substrate, a pseudomorphic strained layer disposed thereover that comprises at least one of AlN, GaN, InN, or an alloy thereof, and, disposed over the strained layer, a semiconductor layer that is lattice-mismatched to the substrate and substantially relaxed.
75 Citations
33 Claims
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1-20. -20. (canceled)
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21. A light-emitting device comprising:
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a single-crystal aluminum nitride substrate having opposed top and bottom surfaces, the bottom surface comprising a non-planar pattern enhancing photon extraction therefrom; disposed over the top surface of the substrate, a bottom contact layer comprising doped AlnGa1-nN, n being less than 1; disposed over the bottom contact layer, a multiple-quantum well layer comprising a plurality of periods each comprising a strained AlxGa1-xN barrier and a strained AlyGa1-yN quantum well, x and y being different by an amount facilitating confinement of electrons and holes in the multiple-quantum well layer; disposed over the multiple-quantum well layer, a doped cap layer comprising AlzGa1-zN providing electrical contact to at least one layer therebelow; disposed between the multiple-quantum well layer and the cap layer, an undoped strained graded AlwGa1-wN layer, the composition of the graded layer being graded over its thickness from a value of w being approximately equal to x to a value of w being approximately equal to z, and the graded layer comprising therewithin a distribution of polarization charge; and disposed over and in contact with the cap layer, a metallic contact layer, the contact layer comprising an ultraviolet reflector for redirecting light emitted by the multiple-quantum well layer toward the substrate. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification