Surface Second-Harmonic Generation in Molecularly Bonded InGaP Waveguides on Si Thermal Oxide

The heterogeneous integration of III-V semiconductors (III-Vs) with the Si platform allows to merge photon sources with Si electronics while enabling the use of micro-electro mechanical systems (MEMS) mature processing techniques. The inherent insufficient quality of III-Vs' native and thermal oxides make imperative the use of deposited interfacial oxide layers for bonding full wafers [1]. The traditional method of choice to overcome that problem is plasma-enhaced chemical vapor deposition due to its low deposition temperature, which prevents the dissociation of III-Vs [1]. Here, we present further developments on a novel technique [2], greatly enhancing its Si platform compatibility. As a result, the transfer of top cladded InGaP waveguides (WGs) to a standard Si wafer with wet-thermal oxide thickness of 4μm has been experimentally demonstrated. Consequently, double inverse-tapered WGs can be realized enhancing the in/out-coupling while offering unprecedented freedom in the target substrate design constrains due to the well-known Bosch Si etching process. The surface optical nonlinearity of the transferred WGs has been used for modal phase-matched second-harmonic generation (SHG) [3].