Multicomponent Sb-based solid solutions grown from Sb-rich liquid phases

We developed the LPE growth technology of InGaAsSb, AlGaAsSb and AlGaInAsSb layers from Sb-rich liquid phases on GaSb substrates. All multicomponent heterostructures were studied by double crystal X-ray diffraction. InGaAsSb layers were grown in both sides of the miscibility gap, near GaSb and near InAs. From a study of the variation of the rocking curves´ halfwidth with the supercooling temperature of the In-Ga-As-Sb liquid phases the technological growth conditions were optimized. In the case of AlGaAsSb the GaSb substrate is eroded in contact with a saturated Al-Ga-As-Sb liquid due to the high non equilibrium degree on this system and the erosion increases with Al concentration. One of the techniques to diminish the erosion consists in increasing the initial supercooling but in this system, in the investigated area of compositions, it is impossible because of the low critical supercooling (ΔT_cr) of the liquid phase. We have conceived and developed a method to control ΔT_cr by adding In to the Al-Ga-As-Sb liquid phase. It was found that when the In concentration increased the ΔT_cr also increased. So the transition from the quaternary AlGaAsSb to the pentanary AlGaInAsSb allowed us to decrease the erosion process. It is shown that high quality multicomponent Sb-based solid solutions can be grown by the developed technique with Sb as a solvent