III-V/Si Wafer Bonding Using Transparent, Conductive Oxide Interlayers

Abstract

We present a method for low temperature plasma-activated direct wafer bonding of III-V materials to Si using a transparent, conductive indium zinc oxide interlayer. The transparent, conductive oxide (TCO) layer provides excellent optical transmission as well as electrical conduction, suggesting suitability for Si/III-V hybrid devices including Si-based tandem solar cells. For bonding temperatures ranging from 100${}^{\circ }$C to 350${}^{\circ }$C, Ohmic behavior is observed in the sample stacks, with specific contact resistivity below 1 $\Omega$cm${}^2$ for samples bonded at 200${}^{\circ }$C. Optical absorption measurements show minimal parasitic light absorption, which is limited by the III-V interlayers necessary for Ohmic contact formation to TCOs. These results are promising for Ga${}_{0.5}$In${}_{0.5}$P/Si tandem solar cells operating at one sun or low concentration conditions.