Comprehensive study of GaAs MOSFETs using gadolinium oxide and praseodymium oxide layers

The high-dielectric-constant (high- k) gadolinium oxide layer (Gd ₂O₃) and praseodymium oxide layer (Pr₂O ₃) are demonstrated as gate dielectric insulator materials in GaAs metal-oxide-semiconductor field-effect transistors (MOSFETs) using in situ high oxygen flow rate electron-beam deposition technology. The dielectric constants of the Gd₂O₃ and Pr₂O₃ layers developed in this study were 9.2 and 9.8, respectively. The Schottky gate turn-on voltages of GaAs MOSFETs with Gd₂O₃ and Pr ₂O₃ insulators were 2.23 and 2.25 V, respectively, representing an improvement on the conventional p-type high electron mobility transistors (0.85 V). Moreover, the Gd₂O₃ MOSFETs had a higher thermal stability and thermal linearity than the Pr₂O ₃ MOSFET (temperature range 100-400 K) due to its high binding energy, as revealed by X-ray photoelectron spectroscopy.