Abstract

Recent developments in heteroepitaxy have made possible the growth of high quality III–V semiconductors on Si substrates offering the possibility of monolithic integration of III–V devices with Si integrated circuits. We report the first heteroepitaxial growth of device-quality strained layer GaSb on 3-in. diam (100) oriented n-doped Si wafers by MBE and describe the operation of optically pumped GaSb lasers having a performance level that is similar to that obtained from layers grown on GaSb substrates.^1,2 The layer growth is shown schematically in Fig. 1. A 150-A thick AlSb nucleation layer was grown on the Si with a Sb₂ stabilized surface condition at ~ 4 monolayers/min to initiate the growth of the polar III–V on the nonpolar Si. This was followed by a 0.6-μm thick AlSb buffer layer and a 50-period superlattice of alternating 100-Å thick GaSb and AlSb layers grown at rates of 1.0 and 0.6 μm/h, respectively. These layers block or bend away from the surface the dislocations resulting from ~12 % lattice mismatch, leaving the subsequent layers essentially free of dislocations. The lattice dimensions of the GaSb and Al_0.4Ga_0.6Sb normal to the layers are less than for bulk crystals indicating the layers are strained in the plane of the layers. It is largely due to the difference in thermal contraction of the III–V relative to Si on cooling from the growth temperature. Parts of the wafer were thinned to ~75 μm and cleaved into 254-μm long bars. A Nd:YAG laser emitting 250-ns long pulses at a 100-Hz repetition rate was used as the optical pump.

© 1986 Optical Society of America