An Investigation on Structural and Electrical Properties of RF-Sputtered Molybdenum Thin Film Deposited on Different Substrates

Abstract

Molybdenum (Mo) is the prominent choice as the back contact for various thin film solar cells such as CIGS, CZTS and CdTe. Physical vapour deposition (PVD) technique especially sputtering process has been chosen as the foremost method to deposit Mo thin film on top of desired substrate due to ease of parametric control of growth conditions. In this paper, we reported the effect of various RF power, operating pressure as well as temperature on Mo films on top of Mo sheet and soda lime glass (SLG) deposited using RF magnetron sputtering. Uniform surface morphology was obtained as RF power, operating pressure and deposition temperature were optimised. However, at higher deposition temperature less uniform surface was observed. XRD pattern of Mo films showed two different peak of <200> and <211> in case of Mo sheet and single peak <110> in case of SLG. While peak intensity varies as deposition condition varies in case of Mo films deposited on Mo sheet. Electrical properties of Mo films on both Mo sheet and SLG were improved as RF power and deposition temperature are optimised. On the other hand, electrical properties are affected as operating pressure increased. Lower resistivity of 1.2x10-9 Ω.m and 6.65x10-6 Ω.m were found in case of Mo films deposited on Mo sheet and SLG. Surface roughness of 0.017 nm-19.32 nm were found in case of Mo films deposited on Mo sheet and 0.002 nm-5.04 nm were found in case of SLG. Roughness increased as RF power and deposition temperature increased. However, roughness decreased as operating pressure increased.