Electrical Behavior of Vertical Pt/Au Schottky Diodes on GaN Homoepitaxy

International audienceSchottky barrier diodes on GaN on GaN substrates are fabricated for the purposeof material and technology characterization. The epitaxial layers are grown byMOCVD. I–V measurements as a function of the temperature in the range80–480 K show ideality factor (n) and barrier height (ϕB) variations not following athermionic (TE) model. Consequently, barrier height fluctuations are considered.In the temperature range 280–480 K, an average barrier height of 1.31 eV with arelatively large standard deviation (σ) of 0.15 eV is extracted using this model. Then(T ) variation is also analyzed in order to extract the field sensibility of 1) themean barrier height variation (ρ2 = -0.1) and 2) the barrier height standarddeviation (ρ3 = -15mV). The corrected Richardson plot usingϕB and σ values islinear and gives a Richardson constant of 31.5 A cm² K² close to the theoreticalvalue of 26.4 A cm² K². For a deeper understanding of ϕB fluctuation origins,micro-Raman mapping of the epitaxial layers and deep-level transient spectroscopy(DLTS) are used. μ-RS mappings show compressive strain for diodeshaving suffered electrical breakdown. DLTS analysis shows the presence of ninelevels whose signatures are extracted and nature discussed