Silicon epitaxial regrowth passivation of SiGe nanostructures pattered by AFM oxidation

SiGe quantum devices were demonstrated by AFM oxidation and selective wet etching with features size down to 50 nm. To passivate the devices and eliminate the interface states between Si/SiO2, low temperature regrowth of epitaxial silicon over strained SiGe has been tested. The silicon regrowth on Si0.8Ge0.2 was done by rapid thermal chemical vapor deposition (RTCVD) at 700 degreesC using a hydrogen pre-cleaning process at 800 degreesC and 10 torr. SIMS analysis and photoluminescence (PL) of strained SiGe capped with epitaxial regrown silicon show a clean interface. Nano-gaps between doped SiGe filled and overgrown with epitaxial silicon show an electrical insulating property at 4.2 K.