Surface passivation of c-Si by atmospheric pressure chemical vapor deposition of Al2O3

Atmospheric pressure chemical vapor deposition of Al2O3 is shown to provide excellent passivation of crystalline silicon surfaces. Surface passivation, permittivity, and refractive index are investigated before and after annealing for deposition temperatures between 330 and 520 °C. Deposition temperatures >440 °C result in the best passivation, due to both a large negative fixed charge density (∼2 × 1012 cm−2) and a relatively low interface defect density (∼1 × 1011 eV−1 cm−2), with or without an anneal. The influence of deposition temperature on film properties is found to persist after subsequent heat treatment. Correlations between surface passivation properties and the permittivity are discussed.