Improved Electrical Properties of Cr/ITO Ohmic Contact Using RF Sputtering System

Abstract

In order to obtain a suitable ohmic contact with the lowest resistivity, chromium (Cr) thin films were deposited on a transparent conductive oxide (TCO) Indium Tin Oxide (ITO) by radio frequency (RF) sputtering method in argon atmosphere and its electrical properties were optimized. The deposition of Cr thin film has been performed for the layers with different thicknesses of 150, 300, and 600 nm at constant Ar gas flow of 30 SCCM. Results showed that the lowest contact resistivity belongs to the layer with 600 nm thickness. Furthermore Cr/ITO has been studied for five different RF powers of 100, 150, 200, 250, and 300 W for a 600 nm thickness Cr sample, which showed the lowest contact resistivity. On the other hand Cr/ITO has been studied for different flows of argon gas 10, 30, 50 and 70 SCCM, during the deposition with constant thickness of 600 nm Cr thin films. Our experimental results suggest that the best specific contact resistance was achieved at RF power of 150W, which was 4.7×10−6 Ωm2. The best specific contact for Cr/ITO has been obtained 4.5×10−6 Ωm2 at argon gas flow 10 SCCM with 600 nm thickness.