Improved Pseudomorphic High Electron Mobility Transistor Structures On Ingaas Substrates

Single and double pulse doped pseudomorphic high electron mobility transistor structures with 110-Angstrom-thick InGaAs channel layers have been grown on InxGa1-xAs substrates (x = 0.04; 0.065) and GaAs substrates. For In0.23Ga0.77As channel layers, higher electron mobilities were obtained on In0.04Ga0.96As substrates due to reduced strain. Transmission electron microscopy micrographs on a GaAs-based sample exhibited a roughened selectively doped heterojunction but no detected misfit dislocations. Pseudomorphic structures with In0.27Ga0.73As channel layers were also grown on In0.065Ga0.935As substrates with good transport and optical properties. The properties of the analogous structure grown on GaAs were severely degraded. Transmission electron microscopy micrographs on the GaAs sample showed a very rough selectively doped heterojunction with misfit dislocations. (C) 1997 American Institute of Physics.