Influence of thermally annealed Schottky metal contact on DC and RF behavior of n-GaN Schottky diode

Abstract

In this paper we discuss the influence of thermally annealed Schottky metal contact on DC and RF characteristics of n-GaN Schottky diode. The fabrication of n-GaN Schottky diode started with mesa mask RIE etching and then lift off Al as an ohmic contact annealed at 400degC in N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ambient for 10 min. For Schottky contact lift off Pt, Ni and Pd Schottky metal annealed from 400degC to 600degC for 10 min. DC analysis shows that thermally annealed Pt Schottky metal contact on n-GaN at 400degC improved the (I-V) characteristics maximum barrier height (Phi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> ) 1.10 eV, ideality factor (eta) 1.001 and high breakdown voltage with low leakage current as compared to the Pd and Ni Schottky metal contact. While for RF analysis, s-parameters were calculated up to 10 GHz by using two-port network. Results show that thermally annealed Pt Schottky metal contact shows lower insertion losses as compared to Pd and Ni Schottky metal contact.