Manipulation of stored charge density and polarity in anodic aluminium oxide for silicon solar cell passivation

Abstract

This paper introduces a method to manipulate stored charge density and polarity in anodic aluminium oxide (AAO) for silicon solar cell passivation. The method involves the use of a pulse current source to anodise aluminium layers instead of the typically used constant current/voltage source, with the test structures experiencing positive and negative cycles periodically. By tuning the positive cycle percentage, it is demonstrated that the effective stored charge can be manipulated in a range from -5.2×1011 to 2.5×1012 q/cm2 when the AAO is formed over a thin silicon dioxide layer. Photoconductance decay measurements on symmetrical n-type test structures with ∼ 150 Ω/□ boron-diffused surfaces..