Shimomura Kazuhiko

Successful room temperature lasing of GaInAsP SCH-MQW LD grown on directly-bonded InP/Si substrate was obtained. Threshold current density at 20 degrees C was 1.5 kA/cm(2).

Crystal growth on a Si substrate for the fabrication of a 1.2 µm GaInAsP laser diode is demonstrated via metal organic vapor phase epitaxy and lasing operation in the pulse regime at room temperature was successfully achieved. Direct wafer bonding at 400 °C for the InP thin film and Si substrate is conducted prior to the growth process is adopted. After the bonding process, epitaxial layers are grown for the monolithic integration of InP optical devices on the wafer-bonded InP/Si substrate. The surface after crystal growth is quite smooth and contains less voids. The photoluminescence (PL) intensity of GaInAsP on the InP/Si substrate is almost equivalent to the PL intensity of InP substrate as a reference. After forming a metallic contact at the n-Si and p-InP sides, the chips are cleaved and the current density-light output (I-L) characteristics are measured. The I-L characteristics show that there is a difference in the threshold current density between the InP/Si substrate and InP substrate. The increase in the threshold current density is dependent on the measurement temperature, and that for the InP/Si substrate was as low as 4 kA cm−2.

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.

We have demonstrated for the first time 1.5μm GaInAsP laser on silicon substrate using direct wafer bonding and MOVPE growth. The energy bandgap of bulk crystalline silicon is always a critical issue as it leads to the limitations of Si as light source devices for optical interconnection. We demonstrated the monolithic integration of hetero-epitaxial growth on InP/Si substrate via MOVPE. Our unique approach prior to growth is that we do the adhesion of InP substrate and Si substrate using hydrophilic wafer bonding technique. Using direct wafer bonding method, a successful GaInAsP lasing operation is obtained for the first time for 1.5 μm on InP/Si substrate.

Bonding temperature dependence on the surface conditions and optical characteristics of MOVPE grown GaInAsP/InP laser structure using directly bonded InP/Si substrate were studied. We have changed the temperature for bonding InP and Si substrate between 350 and 450 degrees C. The void density and photoluminescence intensity were examined.

Lasing characteristics dependent on the bonding temperature for 1.5p.m GaInAsP 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 degrees C. The electrical and lasing characteristics dependent on the bonding temperature were compared.

We have developed the integration method for III-V semiconductor devices on silicon platform using epitaxial growth on direct wafer bonded thin film InP-Silicon substrate. We have successfully obtained 2-inch InP-Si substrate with low void density, and attained room temperature operation of 1.5 mu m wavelength GaInAsP laser by MOVPE growth.

Low threshold current 1.5 mu m GaInAsP 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.

We have successfully obtained GaInAsP stripe laser grown on InP/Si substrate by MOVPE. InP/Si substrate was prepared by direct wafer bonding technique using epitaxial grown 1 mu m thickness InP and silicon substrate. 1.2 mu m wavelength GaInAsP 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.

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. (C) 2016 The Japan Society of Applied Physics

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. (C) 2016 The Japan Society of Applied Physics

InP nanowires and InP/GaInAs/InP core-multishell nanowires were successfully grown on an InP(111) B substrate by low-pressure metal organic vapor phase epitaxy (MOVPE) using an indium catalyst. The self-catalytic vapor-liquid-solid (VLS) mode was used to obtain high-quality nanowires in which a deposited indium droplet acts as the catalyst instead of a metal particle, as in the case of the conventional VLS mode. InP core nanowire structures dependent on growth temperature and preheating temperature were obtained. InP/GaInAs/InP core-multishell nanowire structures, densities, and optical properties were investigated at various flow rates of trimethylindium (TMI) during the growth of InP core nanowires and the growth time of the GaInAs shell layer was also studied. The growth volume and density of nanowires were mainly dependent on growth temperature and preheating temperature, respectively. The height of nanowires was dependent on the TMI flow rate in the InP core nanowire growth, and the thickness of GaInAs shell layer was controlled by adjusting the growth time of the GaInAs shell layer. The photoluminescence (PL) intensity increased with increasing nanowire height and the peak wavelength was controlled by adjusting the thickness of the GaInAs shell layer. (C) 2016 The Japan Society of Applied Physics

The core-multishell nanowires of n-InP/ i-GaInAs/ p-InP were successfully grown on an InP(111)B substrate by low-pressure metal organic vapor phase epitaxy (MOVPE) using an indium self-catalyst. The self-catalytic vapor-liquid-solid (VLS) mode was used to obtain high-quality nanowires in which a deposited indium droplet acts as the catalyst instead of a metal particle, as in the case of the conventional VLS mode. An n-InP core nanowires were grown by VLS mode, and GaInAs/InP shells were grown by VPE mode, by supplying trimethylindium (TMI), tertiarybutylphosphine (TBP), triethylgallium (TEG), and tertiarybutylarsenic (TBAs), respecttively, and their dopant were ditiarybutylsilicon (DTBSi) and diethylzinc (DEZn). Spin-on-glass and patterned electrodes were formed, and voltage-current characteristics of n-InP/ i-GaInAs/ p-InP core-multishell nanowires have shown typical rectifying characteristics of p-i-n diode, and the ideality factor of this sample was n=3.2.

We have successfully obtained 2-inch mirror like surface InP/Si wafer by using direct bonding. GaInAsP-InP double-hetero structure laser was grown on InP/Si substrate by MOVPE. Low temperature lasing was attained and show their characteristics.

Stranski-Krastonogh QDs have been successfully grown on InP/Si substrate fabricated by wafer direct bonding. According to PL and AFM measurements, almost the same size and peak wavelength have been obtained with the InP substrate.

We have successfully demonstrated the growth of InP/GaInAs core-multishell nanowires employed the self-catalytic VLS mode and VPE mode of MOVPE, and obtained the photoluminescence spectrum dependent on the thickness of GaInAs shell layer.

We have successfully obtained lasing characteristics of GaInAsP double-hetero laser diode grown on directly bonded InP/Si substrate through the InP-Si interface carrier injection. Directly bonded InP/Si substrate was prepared by 1 mu m thickness InP and Si substrate. Threshold current and spectrum of laser diode on InP/Si and InP substrate are discussed.

We have successfully obtained lasing characteristics of GaInAsP double-hetero laser diode grown on directly bonded InP/Si substrate through the InP-Si interface carrier injection. Directly bonded InP/Si substrate was prepared by 1 mu m thickness InP and Si substrate. Threshold current and spectrum of laser diode on InP/Si and InP substrate are discussed.

Current-injected light emission was confirmed for metal organic vapor phase epitaxy (MOVPE) grown (Ga)InAs/InP quantum dots (QDs) on directly bonded InP/Si substrate. The InP/Si substrate was prepared by directly bonding of InP thin film and a Si substrate using a wet-etching and annealing process. A p-i-n LED structure including Stranski-Krastanov (Ga) InAs/InP QDs was grown by MOVPE on an InP/Si substrate. No debonding between Si substrate and InP layer was observed, even after MOVPE growth and operation of the device under continuous wave conditions at RT. The photoluminescence, current/voltage, and electroluminescence characteristics of the device grown on the InP/Si substrate were compared with reference grown on an InP substrate. (C) 2015 The Japan Society of Applied Physics

InP nanowires were successfully grown on an InP(111)B substrate by low pressure metal organic vapor phase epitaxy (MOVPE) using an indium catalyst. The self-catalytic vapor-liquid-solid (VLS) mode was used to obtain high quality nanowires where a deposited indium droplet acts as the catalyst instead of a metal particle, as with the conventional VLS mode. The nanowire characteristics are discussed as a function of the preheating and growth temperatures used with this method InP nanowires vertically aligned on (111) orientation were obtained and the nanowire density was dependent on the preheating temperature, while the total growth volume was mainly dependent on the growth temperature. From these results, the optimal growth conditions to produce InP nanowires with small diameter, high density, and lower dispersion have been determined. (C) 2014 Elsevier B.V. All rights reserved.

GaInAs/InP multi quantum wells light-emitting diode, emitting at 1.3-mu m, was fabricated by metal organic vapor phase epitaxi on wafer bonded InP/Quartz substrate. The device has been operated under continuous wave operation at room temperature.

The surface conditions of thin film InP epitaxial layers transferred to a Si substrate have been investigated in terms of void size, density, and area occupied by the voids, by changing the annealing temperature and ramping periods to reach the annealing temperature of 400 degrees C. Through a long ramp annealing time of 45 h, the voids generated were downsized by up to two orders of magnitude, and the total number of voids also greatly decreased compared that for the typical annealing process at 400 degrees C. This resulted in a reduction of the InP surface area occupied by voids from 3.96 to 0.03%. Then, successful fabrication of void-free 50 mm InP/Si substrates without forming any outgassing channels has been I demonstrated. (C) 2014 The Japan Society of Applied Physics

The surface conditions of thin film InP epitaxial layers transferred to a Si substrate have been investigated in terms of void size, density, and area occupied by the voids, by changing the annealing temperature and ramping periods to reach the annealing temperature of 400 °C. Through a long ramp annealing time of 45 h, the voids generated were downsized by up to two orders of magnitude, and the total number of voids also greatly decreased compared that for the typical annealing process at 400 °C. This resulted in a reduction of the InP surface area occupied by voids from 3.96 to 0.03%. Then, successful fabrication of void-free 50 mm InP/Si substrates without forming any outgassing channels has been demonstrated.