Ni based planar Schottky diodes on gallium nitride (GaN) grown on sapphire

In this work, Schottky barrier diodes (SBD), made using lift-off process, were realized on low doped n-type GaN grown by MOCVD. Schottky to Schottky structures were first realized, allowing to select convenient process parameters that reduce the leakage current, such as surface cleaning, thickness of the metallic contact and annealing time or temperature. Then, planar Schottky diodes were patterned and characterized to extract barrier height and ideality factor. Results show that good rectifying behaviour can be obtained with a 300nm thick Ni Schottky contact annealed in RTA at 450°C during 3 min under Argon. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)