Influence of Surface Defects on the Characteristics of GaN Schottky Diodes

Abstract

We have studied the fabrication of Pt/Au Schottky diodes on n-type GaN. We show that the electrical characteristics of the diodes are strongly dependent on the surface chemical treatment before the metal deposition. Lowest leakage currents were obtained by the use of a HC1 solution. We also show that annealing the diode at a moderate temperature (400°C) leads to reduced reverse currents. In order to explain these results, we measured the density of deep levels in the Schottky diode depletion region before and after the annealing process. We did not observe any significant difference in the bulk density of defects due to the anneal. We also studied the temperature dependence of the reverse currents and found a low activation energy. Our results are interpreted in terms of electrical defects at the metal-GaN surface.

Effect of annealing temperature on the electrical, structural and surface morphological properties of Ru/Ti Schottky contacts on n -type InP

“…These results indicate that the electrical properties of the Ru/Ti/n-InP SBD strongly influenced by the annealing temperature. According to Duboz et al [14], the lower value of the barrier height for the sample annealed at higher temperature can be attributed to reduction in the density of interfacial defects. The modification of the defect density by annealing could change the pinning at the Fermi level resulted in a change of the barrier heights.…”

Investigations on the nonidealities in Pd/n-GaN Schottky diodes grown by MOCVD

“…Detailed Schottky diode studies were reported for various metal contacts on n-GaN [7][8][9][10][11][12]. Recently, the dependence of device parameters on threading dislocations in GaN based light emitting diodes (LEDs) and Schottky diodes fabricated on different substrates or templates were reported [13][14][15].…”

Thermal stability of Schottky contacts on strained AlGaN/GaN heterostructures

“…This improvement can be attributed to the reduction of density of interfacial defects. 18 However, as the annealing temperatures increased further, the I -V characteristics of SCs deteriorated in both cases. The degradation is attributed to the creation of shunt paths 11 due to the deep diffusion of Ni atoms into GaN layer, as illustrated in Fig.…”