Hybrid InGaAsP/SiC Fabry-Perot Laser on Low Thermal Impedance SiC Substrate via Adhesive Wafer Bonding Technique

Abstract

Herein, a new approach of semiconductor laser is developed by integrating a vertical 1500-nm ridge-type InGaAsP P-i-N heterojunction Fabry–Pérot laser structure onto a SiC substrate via BCB adhesive wafer bonding technique. By taking advantage of a high thermal conductivity SiC substrate and thin <50 nm BCB, the whole laser structure with a low thermal impedance (TI) of 19.7 K/W was observed by measuring the wavelength shift, overall dissipated power, and substrate temperature, which could thus yield a high continuous wave output power of 30.4 mW. The laser exhibited a higher optical power level and a lower threshold current density than two other lasers with the same active regions but with InP and silicon-on-insulator (SOI) substrates, confirming that the low TI of the SiC substrate contributed to the laser performance enhancement. By simulating TI in structures with different substrate, it shows that the high thermal conductivity in SiC substrate with thin BCB can still be beneficial to the overall TI. The luminescent peak wavelength of the laser with the SiC substrate exhibited a strong blue-shift phenomenon, even at current densities above the threshold current density, indicating that the low TI of the substrate considerably reduced laser self-heating caused by current injection. A III–V material heterogeneously integrated into a SiC substrate scheme using the wafer bonding technique could have wide applications in high-performance, low-cost, process-facilitated photonic integrated circuits.