Structural characterization of InGaAs/InAlAs quantum wells grown on 0 (111)-InP substrates

Recent studies on HEMT structures according to their growth orientation have attracted much interest from the viewpoint of physics and novel device applications. However, the optimization of their properties needs a high degree of crystalline quality. In this work, the structural characteristics of the layers present on InGaAs/InAlAs HEMT structures grown on (111)-InP substrates have been analyzed by atomic force and transmission electron microscopies. The presence of a strained quantum well induces a defect structure and surface morphology quite different from those observed in similar samples without the quamtum well. These results show that an accurate control of the growth conditions is necessary to obtain acceptable structural quality for (111) devices.