Plastic relaxation in metamorphic high electron mobility transistor structures was investigated by means of X-ray reciprocal mapping and high-resolution transmission electron microscopy. The X-ray data indicated that In(Ga)AlAs buffers, with a linearly graded buffer and an inverse step, were completely strain-compensated at the buffer/active-area interface. High-resolution transmission electron microscopy revealed a reduction in the dislocation density from 109 to 106/cm2 through the buffer. Optimized metamorphic high electron mobility transistor structures were found to exhibit a root-mean-square roughness of about 2nm.

Strain Relaxation and Dislocation Filtering in Metamorphic High Electron Mobility Transistor Structures Grown on GaAs Substrates. D.Lubyshev, W.K.Liu, T.R.Stewart, A.B.Cornfeld, X.M.Fang, X.Xu, P.Specht, C.Kisielowski, M.Naidenkova, M.S.Goorsky, C.S.Whelan, W.E.Hoke, P.F.Marsh, J.M.Millunchick, S.P.Svensson: Journal of Vacuum Science and Technology B, 2001, 19[4], 1510-4

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