Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 19: Symposium 50 Jahre Solarzelle

HL 19.5: Talk

Tuesday, March 9, 2004, 17:15–17:45, H15

The Crystalline Silicon Solar Cell - Its History, Achievements And Perspectives — •G. Willeke — Fraunhofer ISE, Heidenhofstr. 2, D-79110 Freiburg, Germany

With a long history of successful market deployment, the crystalline silicon solar cell currently celebrates its 50th anniversary. On this occasion it is useful and appropriate to analyse the rate of progress in the past and to highlight its further development potential for the markets to come. Subsequent to finding a suitable market in space 5 years after its conception, crystalline silicon developed into the workhorse technology of the terrestrial power market which was stimulated by the oil crises 25 years ago. In the first 25 years of its existence, all the technological features were already demonstrated on a lab-scale that are now incorporated in the mass-manufacturing lines such as a screen printed front finger grid, textured and passivated surfaces, the back surface field and even the now very successful block-casting technique was researched then. The early terrestrial devices in the late 70s took a great benefit from the space development and first modules were 8 inch single crystalline wafers. In comparison, today’s product is made from 125mm quasi-square substrates (150mm full square are currently under development) with module efficiencies in the range of 11-15 efficiency of 6 technology. The wafer size here has increased from 10x10 cm² to 12.5x12.5 cm² (15x15 cm² being introduced into manufacturing). In all these technologies the wafer thickness has been hardly reduced in this quarter century from 400 m² to 300 m². The task of the next decade will be to bring 20 technology into production, bring the wafer size to 20x20 cm² and at the same time reduce the wafer thickness considerably. That the manufacturing of 50 m² thin crystalline silicon wafers into 40 m² thin 20 technique LFC, has been recently demonstrated in our laboratory. A challenge lies in the massproduction of 50 m² wafers with cost-effective methods.