Preparation of Al2O3 thin films by RS-ALD and edge passivation application for TOPCon half solar cells

A rotary spatial atomic layer deposition (RS-ALD) method is proposed for the preparation of high-quality Al2O3 2 O 3 thin films and its application to the edge passivation of tunnel-oxide passivated contact (TOPCon) half solar cells. The high- quality Al2O3 2 O 3 thin films were prepared on silicon wafers by optimizing the process conditions with a process pressure of 4 Torr and a trimethylaluminum (TMA, (CH3)3Al) 3 ) 3 Al) flow rate of 300 sccm. The Al2O3 2 O 3 thin films were annealed to analyse the transformation of the film crystal structure, surface morphology, and passivation properties. Compared to the half solar cells without edge passivation, the efficiency of the cell with only deposited Al2O3 2 O 3 increased by 0.098%, and the module power increased by 3.08 W. The efficiency of the cell with deposited Al2O3 2 O 3 + annealing increased by a further 0.021-0.119 %, and the module power increased by a further 0.68-3.76 W.