RF Performance of Diamond Metel–Semiconductor Field-Effect Transistor at Elevated Temperatures and Analysis of its Equivalent Circuit

Abstract

Temperature dependent DC and RF characteristics of p-type diamond metal–semiconductor field-effect transistors (MESFETs) on hydrogen-terminated surfaces are investigated. The device is thermally stable up to 100 °C, because it does not deteriorate at all at higher temperatures. Temperature coefficients of transconductance (gm), drain conductance (gds), gate–source capacitance (Cgs), gate–drain capacitance (Cgd), cut-off frequency ( fT), and maximum drain current (Ids) were obtained from small-signal equivalent circuit analysis. The cut-off frequency ( fT) is almost totally independent of temperature. Intrinsic gm, gds, and Cgs decrease with increasing temperature. Cgd is almost totally independent of temperature. The threshold voltage shifts to the negative side with increasing temperature. We propose a band model of an Al-gate contact/H-terminated diamond to explain the temperature dependence of these components.