Electrical properties of crystalline YSZ films on silicon as alternative gate dielectrics

Abstract

Crystalline yttria-stabilized zirconia oxide (YSZ) film was successfully deposited on a silicon wafer without an interfacial amorphous SiO2 layer. The film with equivalent oxide thickness teox down to 1.77 nm shows negligible hysteresis and low interface state density, less than 3 × 1011 cm-2 eV-1. The leakage current density for teox = 1.77 nm film, 1.5 × 10-5 A cm-2 at 1 V bias voltage, is five orders of magnitude lower than that for SiO2 with the same equivalent oxide thickness. The results demonstrate that an ultra-thin YSZ film has sufficient resistivity against the formation of an underlying amorphous layer, and can be a promising gate dielectric replacing SiO2 to reduce the feature size of devices.