CHEETAH WEBINAR - Overview of lift-off technologies for kerfless crystalline silicon material for PV applications
Webinar - March, 9th 2017 - 14:00 – 15:00 CET
Hariharsudan Sivaramakrishnan Radhakrishnan and Kris Van Nieuwenhuysen
One of the key drivers in wafer-based c-Si PV world is the increasingly efficient use of silicon, primarily as a means to reduce costs per Watt-peak (Wp) and per unit area. As a result of this, there has been an explosion of research and development, starting in the late 1990s, in the area of lift-off and layer transfer techniques aimed at producing ultra-thin films of crystalline silicon as a replacement for standard thick crystalline silicon wafers. In a cost-sensitive PV industry, these lift-off methods could enable strong cost reductions by (1) allowing production of ultra-thin wafers (a factor of 3-4 thinner than today’s wafer) (2) short-cutting several energy-intensive processes in the wafer production value chain, and (3) enabling kerfless wafer production.
This webinar offers a general overview of all technologies developed worldwide for producing kerfless silicon material and will zoom in on the approach and the results obtained in Cheetah so far.
Foils of 80 µm up to 120 µm are grown in an in-line high-throughput CVD reactor and 50 µm layers are grown in a reference single-wafer CVD tool. Handling during the different processing steps becomes an important issue when dealing with very thin wafers. Therefore, a first yield study is made for very thin wafers in a semi-industrial line and first process adaptations are proposed for manual handling of 50 µm foils.