Thermal Stress and Dislocation Density in Undercut GaAs on Si

Abstract
Thermal stress and dislocation density in undercut GaAs on Si(UCGAS) in which the GaAs/Si interface was partially eliminated by post-growth processing were investigated. Thermal stress of less than 2×108 dyn/cm2 was obtained in the area that is large enough for practical applications. The dislocation density was also reduced to less than 5×105 cm-2 by growing strained-layer superlattice (SLS) and GaAs layers on the UCGAS. The dislocation reduction was due to the fact that the UCGAS was free from the stress-induced dislocations during cooling after the growth. As a result, photoluminescence peak wavelength and peak intensity measured in the UCGAS have become almost the same as those in homoepitaxial GaAs.