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

Abstract

Aluminum oxide (AlO x ) 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 AlO x 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 AlO x film deposited at 400 °C exhibited the best S max value of 2.8 cm/s, and the passivation quality was comparable to that of AlO x 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 AlO x films deposited by MCVD consisted of an AlO x layer and a Si-diffused AlO x layer. In addition, it is important for the layers to be thick enough to obtain high-quality passivation.

Effect of the Ti/Si ratio of spin coating solutions on surface passivation of crystalline silicon by TiOx–SiOxcomposite films

“…To date, a variety of methods have been reported for the preparation of Al 2 O 3 films, including atomic layer deposition (ALD) and chemical vapor deposition (CVD). [10][11][12][13][14] Another material that has received attention for use in passivation layers is titanium oxide (TiO 2 ), which has been extensively employed in antireflection layers. 15,16) Owing to TiO 2 having a refractive index of 2.3, Richards proposed the suitability of this material for application in passivation and antireflection films.…”