Comprehensive characterization of vertical GaN-on-GaN Schottky barrier diodes

This paper reports comprehensive characterization of vertical GaN-on-GaN Schottky barrier diodes (SBDs) fabricated on free-standing GaN substrates. The GaN active layer properties are evaluated by atomic force microscopy (AFM), secondary-ion mass spectrometry (SIMS), micro-Raman spectroscopy, cathodoluminescence (CL), and deep-level transient Fourier spectroscopy (DLTFS). The GaN SBDs exhibit near-unity ideality factor (n = 1.1), promising Schottky barrier height (SBH) of Phi(B) = 0.82 eV, low turn-on voltage similar to 0.56 V, leakage current density of J(R) < 5.5 x 10(-6) Acm(-2) at -100 V, breakdown voltage V-BR < -200 V, and less interface state density (N-SS < 5 x 10(12) eV(-1) cm(-2)) at the Ni/GaN Schottky contact. The forward and reverse current transport mechanisms of the SBD are identified by fitting analysis of measured J-V. Weak temperature dependence of Phi(B) and n is detected from I-V-T measurements. Similar traps at E-C - 0.18 eV and E-C - 0.56 are identified in the various SBDs from DLTFS, signifying that these traps are omnipresent defects in the epilayer.

Automated summary

This paper reports the comprehensive characterization of vertical GaN-on-GaN Schottky barrier diodes (SBDs) fabricated on free-standing GaN substrates. The properties of the GaN active layer were evaluated using various techniques, and the GaN SBDs demonstrated promising performance with near-unity ideality factor, high Schottky barrier height, low leakage current density, and low interface state density.