Effect of various surface treatments on adhesion strength of magnetron sputtered bi-layer Molybdenum thin films on soda lime glass substrate

CuInGaSe2 (CIGS) solar technology is leading thin film technology with champion photo-conversion efficiency exceeding 22%, stepping towards rapid commercialization. Sputtered, chemically inert, well adhered highly conducting Molybdenum (Mo) thin film back contact on soda lime glass (SLG) substrate is essential for high photoconversion efficiencies in CIGS modules. The challenge in Mo deposition by sputtering lies in obtaining adherent films while retaining high conductivity, essential for CIGS thin film solar cells and various semiconductor device applications as the metal contact. Apart from deposition conditions, the adhesion of the thin film is also dependent on surface activation of a substrate. In the present work, influence and comparison of various surface treatment methods such as alkali treatment, ultrasonication and plasma treatment on large area SLG substrates subsequently sputtered with Mo had been investigated in detail. The surface of treated SLG substrates was characterized by Water contact angle, AFM, and XPS. Further, investigation of residual stress and adhesion strength of sputtered bilayer Mo thin films on the surface treated SLG are being reported.