Detection of stable positive fixed charges in AlOx activated during annealing with in situ modulated PhotoLuminescence

Abstract An in situ Modulated Photoluminescence (MPL) measurement setup mounted on a Plasma Enhanced Chemical Vapor Deposition (PECVD) reactor is described. A method for deriving the actual minority carrier lifetime at the specific injection level of 1.1015 cm−3 is presented. This tool was used in a case study to monitor the passivation properties of aluminum oxide (AlOx) thin films upon annealing. Interesting kinetics, such as a drop of lifetime at temperatures higher than 250 °C along with a recovery of the lifetime during the cooling phase, are shown. Moreover, these in situ results combined with ex situ studies allowed us to demonstrate the formation a stable high positive fixed charge density in the AlOx layer (+1.1012 cm−2) as a consequence of the combination of annealing and light exposure.