III-V Light-Emitting Diodes on Silicon by Hydrogel-Mediated Wafer Bonding

Abstract

Monolithic on-chip integration of III–V compound semiconductor light-source components particularly on Si platforms is thought to be an important key technology in modern optoelectronics. Hydrogel-mediated semiconductor wafer bonding is an emerging technique for heterogeneous materials integration, simultaneously forming interfaces with high mechanical stability, electrical conductivity, optical transparency, and surface-roughness tolerance [K. Kishibe and K. Tanabe, Appl. Phys. Lett., 115, 081601 (2019)]. So far, its experimental demonstration has been limited to homogeneous Si/Si bonding and an application of solar-cell device. Here we demonstrate the fabrication and operation of a III–V light-emitting diode on Si, via heterogeneous GaAs/Si hydrogel-mediated wafer bonding. The bonding process is carried out in ambient air at room temperature, and therefore can potentially provide significant cost and throughput advantages in device production. Bonding with an unpolished back surface of semiconductor wafer with a micrometer-scale roughness is realized thanks to the deformability of hydrogel. The luminescence characteristics of the bonded device on Si are measured comparable to an unbonded reference. Stable operations of the device at over 70 °C and for over 100 h are demonstrated. Our experimental results verify the further suitability of the hydrogel-mediated semiconductor bonding scheme for optoelectronic device applications.