Raytheon Company

Theodore D Kennedy

William E Hoke

Dean J Baumgartner

Mark S Hunter

David Drew Raines

David S Veldhuizen

Brian D Schultz

Mitchell S Edbauer

John Logan

Amanda Kerr

Peter J Lemonias

Farminder S Anand

Apparatus and associated methods relate to forming an epitaxial layer of aluminum on an aluminum-nitride compound. The aluminum is epitaxially grown on the crystalline aluminum-nitride compound by maintaining temperature of a crystalline aluminum-nitride compound below a cluster-favoring temperature threshold within a vacuum chamber. Then, the crystalline aluminum-nitride compound is exposed to atoms of elemental aluminum for a predetermined time duration. The aluminum is epitaxially grown in this fashion for a predetermined time duration so as to produce a layer of epitaxial aluminum of a predetermined thickness. Such epitaxially-grown mono-crystalline aluminum has a lower resistivity than poly-crystalline aluminum.

Epitaxial growth of aluminum on aluminum-nitride compounds

A structure having: a nucleation layer; and a Group III-Nitride structure disposed on a surface of the nucleation layer, the Group III-Nitride structure comprising a plurality of pairs of stacked Group III-Nitride layers, each one of the pairs of layers having a lower layer having a 3D growth structure and each one of the upper one of the pairs of layers having a 2D growth structure. Each one of the lower layers at completion has a surface roughness greater than a surface roughness at completion of an upper one of the pair of layers. Interfaces between each one of the upper layers and each one of the lower layers of the plurality of pairs of stacked Group III-Nitride layers have crystallographic dislocation combinations and/or annihilations therein.

Group III-nitride structure having successively reduced crystallographic dislocation density regions

Apparatus and method for growing and observing the growth of epitaxial layers on a wafer. The apparatus includes: epitaxial growth apparatus; a source of light mounted to illuminate an entire surface of the wafer in the apparatus during growth of the epitaxial layer on the entire surface of the wafer; and apparatus for observing scattering of the light from the entire surface of the wafer during growth of the epitaxial layer on the entire surface of the wafer. The method includes growing the epitaxial layer on a surface of the wafer and observing scattering of the light from the entire surface of the wafer during growth of the epitaxial layer on the entire surface of the wafer. The growing process is varied in accordance with the observation. With an epitaxial layer of gallium nitride (GaN) the entire surface of the wafer is observed for balls of gallium.

Method for continuous, in situ evaluation of entire wafers for macroscopic features during epitaxial growth

A semiconductor structure, e.g., a high electron mobility transistor structure, is formed by using metamorphic growth and strain compensation. The structure includes a substrate, a graded layer over the substrate, a first donor/barrier layer over the graded layer, and a channel layer over the first donor/barrier layer. The substrate has a substrate lattice constant, and the graded layer has a graded lattice constant. The graded layer has a first lattice constant near a bottom of the graded layer substantially equal to the substrate lattice constant and a second lattice constant near a top of the graded layer different than the first lattice constant. The first donor/barrier layer has a third lattice constant, and the channel layer has a fourth lattice constant. The second lattice constant is intermediate the third and fourth lattice constants.

High electron mobility transistor

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Derry, NH, United States of America

Theodore D Kennedy