Low-temperature fabrication and characterization of Ge-on-insulator structures

Ge-on-insulator structures have been fabricated by wafer bonding and layer transfer techniques. Ultralow bonding temperatures of 150-300 degrees C are employed in order to suppress hydrogen outdiffusion and to produce a low defect density, in an attempt to produce high photocurrent and photoresponse. Thus reducing the hydrogen outdiffusion results in decreased surface roughness. A low defect density is suggested by a low inversion-current leakage of the tunnel diodes. The photoresponse of the Ge-on-insulator detector is also found to increase with decreasing bonding temperature, indicating that defects caused by hydrogen implantation are passivated more effectively. (c) 2006 American Institute of Physics.