On the thermal resistance of metamorphic and lattice-matched InP HBTs: a comparative study

Studies on thermal resistance of InP heterojunction bipolar transistors grown on GaAs (MHBT) and InP (LHBT) substrates are have been reported. A significant increase in the thermal resistance (R/sub th/) for MHBT is observed. R/sub th/ for the MHBT is found to be in the range of 2320 to 2615/spl deg/C/W, which is roughly 80% higher than that of LHBT. This could be attributed the extremely low thermal conductivity of the ternary metamorphic buffer layer as well as the low thermal conductivity of GaAs substrates.