Abstract
GaAs/Si integration receives a lot of attention for both electronic and photonic devices. For example, GaAs/Si-based III-V QWFET and III-V lasers have been demonstrated with superior performances. However, pure GaAs grown on Si is critical due to the lattice mismatch (4%) between these two semiconductors as well as different thermal expansion coefficients. Direct wafer or die bonding of GaAs onto Si wafers is the way that can integrate GaAs on Si. However, removing the bonded substrates could be a waste of material. Furthermore, surface topography between the bonding interfaces often affects the process yield very much. Another approach for GaAs on Si is prior epitaxial growth of Ge/GexSi1-x buffer layer between Si and GaAs, which usually requires special process techniques and the Ge/GexSi1-x buffer layer is usually very thick. In addition, Ge/ GexSi1-x epitaxial growth often requires a high-temperature process condition to achieve high crystal quality. Consequently, the resultant thermal budget and thicker Ge buffer layer could degrade the III-V laser properties at 1.3um wavelength. Previously, rapid melt growth (RMG) of Ge on insulator showed a promising way for integration of high-quality thin Ge on silicon substrate. One characteristic of the RMG method is that the crystal orientation of the growth Ge is a complete replica of the substrate Si and the thickness can be controlled to be very thin. In this paper, we try to use the RMG Ge to substitute the Ge/GexSi1-x buffer layer for epitaxy of GaAs. We use MOCVD to epitaxy GaAs on RMG-Ge. Then we use SEM and AFM to observe the surface morphology and the roughness and use TEM and PL measurement to characterize the crystal quality.