Ion beam deposition of photoactive nanolayers for silicon solar cells

The ion beam deposition of photoactive silicon nanolayers through the bombardment of a single-crystal silicon target with an Ar⁺ ion beam has been analyzed using computer simulation. The model thus derived is consistent with experimental data on the growth of silicon nanolayers on 100-mm-diameter c-Si(p) substrates. The process conditions have been optimized experimentally: pressure, 10⁻⁴ Pa; substrate temperature, 550 ± 50°C; target-substrate distance, 240 ± 5 mm; target-beam angle, 45° ± 2°; accelerating voltage, 450–600 V. Under these conditions, the radial asymmetry of 300-nm-thick c-Si(n) layers is within 10 nm, which reduces the efficiency of c-Si(n ⁺)/c-Si(p)/c-Si(p ⁺) solar cells by no more than 0.3%.