Passivation properties of aluminum oxide films deposited by mist chemical vapor deposition for solar cell applications

摘要

Aluminum oxide (AlOx) films were deposited by mist chemical vapor deposition (MCVD) in air for p-type crystalline silicon, and the effects of the deposition temperature (T-dep) and AlOx film thickness on the maximum surface recombination velocities (S-max) were evaluated. It was found that S-max was improved with increasing T-dep. The AlOx film deposited at 400 degrees C exhibited the best S-max value of 2.8cm/s, and the passivation quality was comparable to that of AlOx deposited by other vacuum-based techniques. S-max was also improved with increasing film thickness. When the film thickness was above 10 nm, S-max was approximately 10 cm/s. From the Fourier transform infrared spectra, it was found that the AlOx films deposited by MCVD consisted of an AlOx layer and a Si-diffused AlOx layer. In addition, it is important for the layers to be thick enough to obtain high-quality passivation. (C) 2015 The Japan Society of Applied Physics