Electrical Characterization of SrTiO₃ Thin Films Grown on Nb-Doped SrTiO₃ Single Crystals

Abstract

SrTiO 3 (100) films homoepitaxially grown on Nb-doped SrTiO 3 (100) substrates with various Nb concentrations and SrTiO 3 (111) films epitaxialy grown on the [111]-oriented Pt thin-film electrode formed on SiO 2 /Si substrates with Ta buffer layers were prepared by the helicon sputtering method. After the top Pt electrode formation, the obtained Pt/SrTiO 3 /SrTiO 3 :Nb metal-insulator-semiconductor (MIS) capacitors and Pt/SrTiO 3 /Pt/Ta/SiO 2 /Si metal-insulator-metal (MIM) capacitors were electrically evaluated by current versus bias voltage characteristic ( I – V ) and capacitance versus bias voltage characteristic ( C – V ) measurements to clarify the specific features of the SrTiO 3 /SrTiO 3 :Nb interface compared with the SrTiO 3 /Pt interface. The existence of a space charge layer at the SrTiO 3 /SrTiO 3 :Nb interface was clearly characterized.