Comparative study of ionic bombardment and heat treatment on the electrical behavior of Au/GaN/n-GaAs Schottky diodes

In this paper, two different cleaning methods before nitridation of the Au/GaN/n-GaAs Schottky diodes are investigated. Batch 1 is cleaned chemically and followed by ionic bombardment in an ultra-high vacuum chamber (UHV). On the other hand, batch 2 is cleaned chemically and followed by heating at 500 degrees C in (UHV) chamber for 5 min. Then, both batches are nitrided at 500 degrees C. As a result, from the analysis of the current-voltage I-V characteristics, the ionic bombardment process gives better ideality factor and lower series resistance than the heating step. Where, n and R-s are equal to 2.17 and 26 Omega for batches 1 and equal to 2.84 and 115 Omega for batch 2, respectively. The barrier height is estimated to 0.36eV and 0.44eV for batches 1 and 2 respectively. As well as, the interface state density N-ss, is lower in the batch 1 compared to the batch 2 where it is estimated equal to 9.11 x 10(12) eV(-1) cm(-2) and 1.86 x 10(13) eV(-1) cm (2) in near mid-gap for batch 1 and 2, respectively. Hence, the ionic bombardment process gives better results than the heating treatment due to the Ar + ion etching of the n-GaAs surface, which cleans the surface and the deep contaminants. Also, after the nitridation process, the interfacial crystallographic dislocations are reorganized by the GaN layer. Conversely, the heating step activates the disorder in the crystal and increases the traps and the interface states.