AVS 49th International Symposium
    Vacuum Technology Tuesday Sessions
       Session VT-TuA

Paper VT-TuA2
Development of Sputtering System for Large-Area Deposition of CuIn@sub1-x@Ga@subx@Se@sub1-y@S@suby@ Thin-Film Solar Cells

Tuesday, November 5, 2002, 2:20 pm, Room C-104

Session: Vacuum System Architecture and Specialized Analytical Techniques
Presenter: N.G. Dhere, University of Central Florida
Authors: N.G. Dhere, University of Central Florida
A.H. Jahagirdar, University of Central Florida
A.A. Kadam, University of Central Florida
V.S. Gade, University of Central Florida
H.P. Patil, University of Central Florida
Correspondent: Click to Email
Manufacturing cost of CuIn@sub1-x@Ga@subx@Se@sub1-y@S@suby@ (CIGS) thin-film modules is expected to become cheaper than that of crystalline silicon modules within 5 years. At present, commissioning and reaching full production of thin film modules is delayed because of the non-availability of turnkey manufacturing plants. Few university laboratories are conducting research on design and construction of PV plants. CIGS thin-film solar cells are being prepared routinely at FSEC on glass and metallic foil substrates for terrestrial and space applications. Earlier the size was limited to 3x3 cm@super2@. This paper presents results of development efforts in design and construction of large-area sputtering system for large-area (15x15 cm@super2@) CIGS thin-film solar cells. The system has the potential of serving as a nucleus of a pilot plant for fabrication of CIGS minimodules. It could be used for simulating full-scale production set-up. Stepper-motor controlled, linear substrate movement and uniform argon distribution set-ups were designed and built. RF tuning network was modified for optimum impedance matching. Initial problems of bowing of the backing diaphragm, possible formation of air pockets, restriction of effective water flow and consequent heating of the target material were resolved by increasing the thickness of the backing plate and redesigning the structural members. Thickness distribution was optimized by modifying the magnetic field distribution in the middle 15-cm portion of the 10x30 cm@super2@ magnetron sputtering sources by selectively removing nickel-coated soft-iron pieces at the rear. The present optimum configuration has resulted in thickness variation of ±3% over 11.5x10 cm@super2@ for Mo, CuGa, In, ZnO, and ZnO:Al layers. Magnetic field is being boosted at extremities to avoid precipitous ~15% drop beyond 11.5 cm and to achieve thickness uniformity of better than ±2% over 12.7x12.7 cm@super2@ and ±3% over 15.3x15.3 cm@super2@ areas.