ABSTRACTAtomic Layer Deposition (ALD) is a gas phase deposition technique for depositing very high quality thin films with an unsurpassed conformality. The main drawback of ALD however is the very low deposition rate (~ 1 nm/min). Recently, record deposition rates for alumina of up to 1 nm/s were reached using spatial ALD, while maintaining the typical assets regarding film quality as obtained by conventional, slow ALD [1]. This allows for ALD at high throughput numbers.One interesting application is passivation of crystalline silicon solar cells. Applying a thin alumina layer is reported to increase solar cell efficiency and enables the use of thinner wafers, thus reducing the main cost factor [2]. In this paper we report on the latest progress made by SoLayTec that delivered a working prototype of a system realizing full area single sided deposition of alumina on 156 x 156 mm2, mono- and multi crystalline silicon wafers for solar cell applications. The alumina layers showed excellent passivation. Based on this concept, a high-throughput ALD deposition tool is being developed targeting throughput numbers of up to 3000 wafers/hr. Finally, we report on the process of commercializing this technology.
Origin of the tunable carrier selectivity of atomic-layer-deposited TiOx nanolayers in crystalline silicon solar cells
