Shimomura Kazuhiko

The lasing characteristics of GaInAsP separate confinement heterostructure (SCH)–multiple quantum well (MQW) laser diodes grown on hydrophilic‐bonded InP–Si substrates are investigated. A hydrophilic bonding method is used to directly bond an InP thin film to a Si substrate, varying the thickness of the InP film and the maximum annealing temperature to optimize the bonding process and minimize void formation. The results show that controlling the annealing temperature and InP film thickness strongly affects the void characteristics, including the void area occupancy, void density, and void angle; it is also found that a lower void area occupancy and a lower void density correlate with reduced threshold current densities in the laser diodes. The laser diodes grown on InP/Si substrates demonstrate threshold current densities that are comparable to or even lower than those grown on InP substrates, provided that the void characteristics are sufficiently controlled. These findings underscore the importance of optimizing substrate fabrication processes to enhance the performance of laser diodes on InP/Si substrates. To improve the efficiency and performance of laser diodes for various applications, future work should focus on further refining these methods and exploring additional factors that influence void formation and laser properties.

This study investigates the effects of different annealing sequences on the hydrophilic bonding of InP/Si substrates for GaInAsP laser diodes (LDs). Several annealing profiles are explored, including a process with slow temperature ramping over a specific range to minimize void formation, and compared to the traditional 8‐hour annealing process, which uses a constant annealing rate. The slow ramping approach within a targeted temperature range is found to be more effective in reducing void formation and improving bonding quality. GaInAsP lasers grown on substrates annealed using this method demonstrate improved performance, showing the potential for optimized annealing processes to enhance the quality and efficiency of bonded LDs.