Comparison of Electrical Properties of Ni/n‐GaN Schottky Diodes on c‐Plane and m‐Plane GaN Substrates

Abstract

The electrical properties of un‐doped and lightly Si‐doped GaN grown on c‐ and m‐plane GaN substrates by metal organic chemical vapor deposition are investigated. The step‐flow growth modes are realized for c‐ and m‐plane GaN epitaxial layer. The carbon contamination in the c‐plane GaN and m‐plane GaN, grown at 1120 °C and V/III = 1000, are found to be 1.4 × 1016 cm−3 and 5.0 × 1015 cm−3, respectively. The m‐plane GaN follows a linear correlation between the carrier concentration and the Si atomic concentration. The Ni/n‐GaN (Si; 1 × 1016 cm−3) Schottky vertical diodes on the c‐ and m‐plane GaN substrates reveal that the reverse current–voltage (I–V) curves are fitted by using the thermionic field emission model under the measured carrier concentration and the Schottky barrier height. The leakage current of the m‐plane GaN is three orders of magnitude larger than the c‐plane GaN, mostly due to the difference in the Schottky barrier height.