Abstract: 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.

Abstract: A method for growing a Group II-VI epitaxial layer on a substrate, said epitaxial layer having an electron mobility greater than 1.5.times.10.sup.5 cm.sup.2 /V-sec at 77.degree. K. and a carrier concentration less than 4.times.10.sup.15 (cm.sup.-3) is described. The method includes the steps of directing a plurality of vapor flows towards the substrate including a Group II metalorganic vapor having a mole fraction in the range of 3.0.times.10.sup.-4 to 4.5.times.10.sup.-4, a Group VI metalorganic vapor having a mole fraction in the range of 2.9.times.10.sup.-3 to 3.5.times.10.sup.-3 and a Group II elemental metal vapor having a mole fraction in the range of 2.6.times.10.sup.-2 to 3.2.times.10.sup.-2. The source of Group II metal is heated to at least 240.degree. C. while radiant energy is directed toward the reactor vessel to warm the zone of the reactor vessel between the Group II metal source and the substrate to at least 240.degree. C.