Chromium thin film deposition on ITO substrate by RF sputtering

E Akbarnejad ,Zohreh Ghorannevis,Ebrahim Soleimani

doi:10.1007/s40094-014-0129-5

Abstract

To obtain a suitable ohmic contact with the lowest resistivity, chromium (Cr) thin films were deposited on transparent conductive oxide indium tin oxide (ITO) by 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 thickness of 150, 300 and 600 nm in constant Ar gas flow of 30 SCCM. Results show 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. Experimental results show that specific contact resistance of Cr/ITO contact decreases in condition of depositing chromium thin films on ITO at higher RF powers. Analysis of SEM has been performed on the samples. The SEM micrographs show Cr thin films have smaller grains at RF power of 150 W, in comparison with other RF powers. The lowest specific contact resistivity for Cr/ITO has been obtained 4.7 × 10−2 Ω cm2 at RF power of 150 W with 600 nm thickness of chromium thin films.

Highlights

Interesting and novel applications in photovoltaic are expected from thin and flexible solar modules, especially in the fields of space, aeronautic, and mobile applications
To obtain a suitable ohmic contact with the lowest resistivity, chromium (Cr) thin films were deposited on transparent conductive oxide indium tin oxide (ITO) by RF sputtering method in argon atmosphere and its electrical properties were optimized
Experimental results show that specific contact resistance of Cr/ITO contact decreases in condition of depositing chromium thin films on ITO at higher RF powers

Summary

Introduction

Interesting and novel applications in photovoltaic are expected from thin and flexible solar modules, especially in the fields of space, aeronautic, and mobile applications. The development of flexible and lightweight Cu (In,Ga)Se2(CIGS) modules has intensified These activities were encouraged by the relatively high small-area cell efficiencies obtained on polymer as well as on metallic substrates. If monolithical integration of the cells is desired to realize solar modules on electrically conducting substrates, the deposition of a dielectric barrier is necessary [4, 5]. The contact between metal and semiconductor can behave ohmic if the Schottky barrier height is zero or even smaller. We report the influence of process parameters on the comparisons of the Cr/ITO ohmic contact properties, the deposition rate, and the structure and properties of Cr coatings deposited by RF sputtering of a metal Cr target in an Ar atmosphere

Chromium deposition with different thicknesses

Chromium deposition at different sputtering RF powers

Findings

Conclusions