The influence of orientation and morphology on the passivation of crystalline silicon surfaces by Al₂O₃

We compare the passivation provided by Al₂O₃ deposited on planar <100> and <111>, and textured <100>, boron-diffused and undiffused crystalline silicon surfaces. The passivation of <111> surfaces is found to be somewhat worse than that of <100> surfaces for the as-deposited films, but improves to similar values after annealing. Higher recombination at textured surfaces compared to planar <111> surfaces can be largely, though not entirely, attributed to the difference in surface area. The passivation of both as-deposited and annealed films is found to improve over time when stored under ambient conditions. This helps give context to the myriad of results reported on planar <100> samples - we expect J0 values measured for Al₂O₃ layers on such surfaces to increase by a factor of ~2 to 3 on textured surfaces.