MOLECULAR-BEAM EPITAXIAL-GROWTH AND STRUCTURAL DESIGN OF IN0.52AL0.48AS/IN0.53GA0.47AS/INP HEMTS

Lattice-matched In0.52Al0.48As and In0.53Ga0.47As layers and two-dimensional electron gas (2DEG) structures have been grown on (100) InP substrates by molecular beam epitaxy (MBE) with dimeric or tetrameric arsenic species. Surface morphology of 0.5-mu-m In0.53Ga0.47As layers is strongly influenced by the As4 to group III flux ratio, and also by the arsenic species used in the growth. The RHEED oscillation study shows that the uses of As2 or higher As4 flux reduce the group III adatoms surface diffusion, hence improving the interface or surface roughness caused by the alloy clustering. This behavior is more obvious in the growth of In0.53Ga0.47As layers than In0.52Al0.48As. Two-dimensional electron mobilities of over 11,080 cm2/V.s at 300 K and 33,500 cm2/V.s at 77 K with sheet charge of 3.9 x 10(12) cm-2 have been achieved from this study.