Surface Recombination of Crystalline Silicon Substrates Passivated by Atomic-Layer-Deposited AlO_x

Abstract

AlO x films as passivation layers for p-type crystalline silicon were prepared by atomic layer deposition with ozone as an oxidant, and the effects of the AlO x film thickness and deposition temperature on the maximum recombination velocity ( S max ) were evaluated. S max is improved by increasing the layer thickness but saturates at a layer thickness of about 30 nm. In the case of samples deposited at room temperature, S max is improved fivefold when the thickness is increased from 20 to 33 nm. S max also improved as the deposition temperature was increased to 300 °C then deteriorated when it was further increased to 350 °C. After postdeposition annealing, we obtained an S max of 8.5 cm/s.