Yuya Onuki

Novel integration method for III-V semiconductor devices on silicon platform

A novel integration method for III–V semiconductor devices on a Si platform was demonstrated. Thin-film InP was directly bonded on a Si substrate and metal organic vapor phase epitaxy (MOVPE) growth was performed by using an InP/Si template. A void-free 2-in. InP layer bonded on a Si substrate was realized, and a low interfacial resistance and ohmic contact through the bonded interface were observed. After the MOVPE process, the as-grown structure was optically active and we observed photoluminescence (PL) intensity comparable to that from the same structure grown on InP as a reference. Furthermore, almost no lattice strain was observed from the InP layer. Then, the epitaxial growth of a GaInAsP–InP double-hetero (DH) laser diode (LD) was demonstrated on the substrate and we observed lasing emission at RT in a pulse regime. These results are promising for the integration of InP-based devices on a Si platform for optical interconnection.

Room-temperature operation of GaInAsP lasers epitaxially grown on wafer-bonded InP/Si substrate

An epitaxially grown GaInAsP/InP double-hetero laser diode (LD) has been demonstrated on a wafer-bonded InP/Si substrate for the first time. The as-grown structure was optically active and exhibited a photoluminescence intensity comparable to that grown on an InP wafer as a reference. Electrodes were formed on both the p-side contact layer and the n-Si underside to fabricate Fabry–Perot LD chips. During these processes, the InP layer remained bonded to the underlying Si substrate. Electrically pumped lasing emission was observed at room temperature under a pulse regime. These results indicate the potential for the high-density integration of InP-based LDs as a light source for optical interconnections.

Lasing characteristics of MOVPE grown 1.5μΜ GalnAsP LD using directly bonded InP/Si substrate

Lasing characteristics dependent on the bonding temperature for 1.5μm GalnAsP LD grown on directly bonded InP/Si substrate was successfully obtained. We have grown laser structure by MOVPE using InP/Si substrate, and fabricated broad area edge-emitted LD. For the preparation of InP/Si substrate, the temperature during direct bonding process was changed to 350, 400, and 450 °C. The electrical and lasing characteristics dependent on the bonding temperature were compared.

Bonding temperature dependence of GaInAsP/InP laser diode grown on hydrophilically directly bonded InP/Si substrate

The bonding-temperature-dependent lasing characteristics of 1.5 a µm GaInAsP laser diode (LD) grown on a directly bonded InP/Si substrate were successfully obtained. We have fabricated the InP/Si substrate using a direct hydrophilic wafer bonding technique at bonding temperatures of 350, 400, and 450 °C, and deposited GaInAsP/InP double heterostructure layers on this InP/Si substrate. The surface conditions, X-ray diffraction (XRD) analysis, photoluminescence (PL) spectra, and electrical characteristics after the growth were compared at these bonding temperatures. No significant differences were confirmed in X-ray diffraction analysis and PL spectra at these bonding temperatures. We realized the room-temperature lasing of the GaInAsP LD on the InP/Si substrate bonded at 350 and 400 °C. The threshold current densities were 4.65 kA/cm2 at 350 °C and 4.38 kA/cm2 at 400 °C. The electrical resistance was found to increase with annealing temperature.

Lasing characteristics of GalnAsP stripe laser integrated on InP/Si substrate

We have successfully obtained GalnAsP stripe laser grown on InP/Si substrate by MOVPE. InP/Si substrate was prepared by direct wafer bonding technique using epitaxial grown 1μm thickness InP and silicon substrate. 1.2μm wavelength GalnAsP double heterostructure laser was grown by MOVPE, and stripe laser was fabricated using standard SiO2 deposition and lithography. Room temperature lasing was obtained under pulsed condition.

Low threshold current of GalnAsP laser grown on directly bonded InP/Si substrate

Low threshold current 1.5pm GalnAsP laser was obtained grown on directly bonded InP/Si substrate using MOVPE. To decrease the threshold current, the thickness and doping condition of p-InP cladding layer were optimized. In the new structure laser, the threshold current became half compared to the previous structure laser, and obtained almost comparable threshold current with the laser grown on InP substrate.