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Fast, faster, SALD

Industrial scalability for solar cell passivation with Spatial ALD

Beneq and Aalto University’s Electron Physics Group studied how Spatial ALD (SALD) can provide surface passivation of planar and black silicon (b-Si), and the results were excellent! Spatial ALD not only provided as efficient surface passivation as temporal ALD, but it also performed faster – the passivation line speed was 9 m/min!

Why can Spatial ALD passivate faster than traditonal temporal ALD, you’re wondering? Let’s let our Process Specialist, Ismo T. S. Heikkinen, who held his poster presentation “Efficient surface passivation of back silicon using spatial atomic layer deposition” at the SiliconPV conference in Freiburg this year, explain.

With the Beneq large-scale Spatial ALD pilot system, the substrate moves along a line under a percursor delivery system called the coating head. The coating head has 11 reconfigurable precursor zones, with the precursors themselves isolated by inert gas zones and exhaust lines. We can coat large area substrates faster along this conveyer belt-like system.”

Illustration of the Spatial ALD reactant delivery system, where precursors are isolated from each other by inert gas zones and exhaust lines.

This is great news for industrial scalability – if you’re in the microelectronics or photovoltaics industry, you’ll definitely want to learn more about our spatial ALD pilots and the possibilities of customizing the Beneq spatial ALD reactors for your specific needs.

The microscopic photograph at the top shows a freshly etched b-Si surface. Photograph courtesy of Toni Pasanen, Aalto University.