Fabrication and Electrical Characterization of High-k LaGdO3 Thin Films and Field Effect Transistors

Abstract

The electrical properties of LaGdO3 (LGO) high-k dielectric thin films prepared by pulsed laser deposition (PLD) on SiOx/p-Si substrate have been studied. The equivalent oxide thickness (EOT) and gate leakage current density (Jg) were determined on metal-oxide-semiconductor (MOS) structures. Capacitance-Voltage characteristics showed negligible hysteresis, ~8 mV. The extracted dielectric constant (k) of LGO layer from the EOT-physical thickness plot was ~21.6 ± 1.7. LGO layers with EOT of 3nm had a Jg ~ 3 x 10-8 A/cm2 at accumulation (Vg=VFB-1). The estimated interfacial trap density at the flatband voltage as determined by Lehovec method was in the range 1012 eV-1cm-2. N-channel LGO metal-oxide-semiconductor field effect transistors (MOSFET) have been fabricated and electrically characterized. The threshold voltage (Vt) was ~0.3V.