Surface-activated Bonding of III-V compound semiconductors and Si for fabricating hybrid tandem solar cells

Abstract

The possibility of the surface-activated bonding (SAB) technologies for fabricating III-V-on-Si hybrid tandem solar cells is discussed. Although the electrical conduction across the bonding interfaces is influenced by the interface states introduced during the surface-activation process, their impacts are likely to be lowered by combining more heavily-doped bonding layers and the annealing process after the bonding. InGaP/GaAs/Si hybrid triple-junction cells are successfully fabricated by bonding III-V heterostructures for InGaP/GaAs double-junction cells and Si cell structures. This means that the bonding interfaces have an enough tolerance against the possible stress during the conventional device process sequence and that the SAB is promising as a practical substitute for the conventional semiconductor growth technologies in fabricating III-V-on-Si tandem cells.