Effect of sputtering on ferromagnet-oxide-silicon spin injection contacts

Abstract

The authors have fabricated metal-oxide-semiconductor (MOS) contacts on silicon for spin injection and detection and characterized them by internal photoemission and capacitance-voltage (C-V) measurements with the aim of extracting the metal- semiconductor effective work-function mismatch that determines the magnetoresistance between such contacts. The authors show that sputter deposition of these contacts induces high levels of negative charge in the oxide localized close to the metal-oxide interface. This is seen to affect the electrostatics of the MOS contact and could thereby impact its contact resistance, and in turn, the magnetoresistance that one can obtain.