LATTICE-MATCHED GROWTH OF INPSB ON INAS BY LOW-PRESSURE PLASMA MOVPE

This contribution reports on results of the growth of InAs and InPSb in low-pressure (20 hPa) plasma MOVPE. Our basic aim was to study the effect of deposition temperature, vapor phase composition and precracking the group V molecules on the growth kinetics and material quality. For InAs growth (TMIn, AsH3) on InAs substrates, material with excellent morphology was achieved in the temperature region of 670 to 770 K (best electrical and morphological quality on SI GaAs at T = 670 K: mu300K = 19,000 cm2/V.s, n300K = 10(17) cm-3). AsH3 precracking did not lead to a further improvement of layer quality. For the epitaxy of InPSb (TMIn, PH3, TESb) the relative rates of incorporation of P and Sb into the solid are of major interest. Preliminary studies of the growth of InP1-xSbx (x < 0.1) (with TESb plasma, PH3 plasma) on InP were performed in order to obtain the vapor-solid distribution relation for the group V elements P and Sb under our growth conditions. For the lattice-matched growth of InP0.69Sb0.31 on InAs, a substantial decrease of the overall PH3 consumption by a factor of 13 with PH3 plasma was noticed. Due to this fact we observed a higher growth efficiency, probably caused by the suppression of prereactions. Layers with electrical properties (on SI InP: mu300K = 3500 cm2/V.s, n300K = 3 x 10(16) cm-3) comparable to those reported in the literature were obtained with and without plasma. In general, the plasma approach leads to an efficient, easily controllable and reproducible process for the lattice-matched growth of InPSb on InAs.