INTERFACE SHARPNESS DURING THE INITIAL-STAGES OF GROWTH OF THIN, SHORT-PERIOD III-V SUPERLATTICES

Superlattices composed of III-V heterostructures have established applications in high-speed electronic and optoelectronic devices. As layer thicknesses are reduced, the role of heterostructure interface sharpness becomes more critical to ensuring high quality two-dimensional growth. In this work, short-period (less than 1 nm) superlattices with active layer thicknesses of 31 nm were investigated to assess interface roughness in the initial stages of growth. X-ray diffraction was used to evaluate interface roughness and to calculate superlattice periodicity. Results suggest that surface roughening by islanding may be promoted by GaAs buffer layers that are 10-100 nm thick. Smoother interfaces were obtained in samples with buffer layers 250 nm and greater.