Review of tools and approaches for inline quality control in high efficiency silicon solar cell production

Multiple tools and methods for the optical and electrical quality control of high efficiency silicon solar cells during their industrial production are available on the market, even more are discussed in the literature. We summarize the possibilities of these tools along the value chain from wafer to cell for the case of passivated emitter and rear cells (PERC) and discuss some showcases. We recommend a broad inline quality control before solar cell production in order to discard wafers with insufficient quality. Especially PL-Imaging can reveal material defects and process variations and thus acts as a versatile tool for the whole production chain. An economic evaluation shows that a CAPEX spending of 250,000 EUR for metrology equipment is already justified if cell efficiency is increased by only 0.03 %abs from a reference efficiency 20.61 % to 20.64 %. Combining technological and economical aspects, this paper gives an overview over recent inline metrology tools and upcoming challenges.