Patent ID: 7341927

Claim:
A method for forming a virtual substrate, comprising: (1) ion implanting a device substrate; (2) bonding the device substrate to a handle substrate; (3) removing a portion of the device substrate thereby leaving a device film bonded to the handle substrate; and (4) removing an upper portion of the device film, thereby leaving a smoother and less defect prone surface on the device film that is suitable for subsequent fabrication of optoelectronic devices; wherein the device and handle substrates are Ge and Si respectively; wherein removing an upper portion of the device film comprises chemically polishing the upper portion of the device film with a damage selective etch; and wherein chemically polishing the upper portion of the Ge film with a damage selective etch comprises etching with a mixture of HF:H2O2:H2O or a mixture of HF:HNO3:C2H4O2 or a mixture of H2O2:H2O.