Electrical Characterization of Gallium Nitride Thin Films Synthesized By Electrochemical Deposition

Abstract

Group III-nitride semiconductor materials show promise in a variety of electronics applications, including diodes, transistors, LEDs and photovoltaic applications. The new generation of semiconductors rely heavily on nanotechnology and advances in nanomaterials. Group III-nitride semiconductor materials such as GaN, AlN and InN are promising materials since their properties are ideal for use in optoelectronic devices, high power and high temperature electronic devices. These materials have wide band gaps between 1.9 and 6.3 eV and, for electronic applications, these materials are usually synthesised by means of chemical vapour deposition or molecular beam epitaxy. These techniques are expensive, therefore we investigated room temperature electrochemical growth to synthesize GaN. The advantages of electrochemical deposition are the controllability of the thickness and surface morphology by varying the deposition parameters, cost-effectiveness, the minimum waste generation, long bath lifetime and easy set-up. In this study, room temperature electrochemical deposition has been used to synthesise GaN nitride on Si substrate. Results: The XRD spectrum of GaN thin films grown under the different conditions are shown in Figure 1. Sample a (1 mA/cm2 for 30 min) and b(3 mA/cm2 for 30 min) were prepared at room temperature. The XRD analysis showed the presence of hexagonal and cubic structure with crystallite sizes calculated from Scherer’s formula were 130 and 140 nm From SEM images, however, the results varied with growth condition. Good quality Schottky diodes were fabricated on the GaN thin films and DLTS measurements were performed. Electron traps with an activation energy of 0.48 and 0.47 eV, were observed in sample a and b, respectively. Figure 1