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

• Published in: Solar energy materials and solar cells Vol. 230; p. 111172
• Main Authors: Desthieux, Anatole, Sreng, Mengkoing, Bulkin, Pavel, Florea, Ileana, Drahi, Etienne, Bazer-Bachi, Barbara, Vanel, Jean-Charles, Silva, François, Posada, Jorge, Roca i Cabarrocas, Pere
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.09.2021; Elsevier BV; Elsevier
• Subjects: Aluminum; Aluminum oxide; Annealing; Biotechnology; Carrier lifetime; Charge density; Computer Science; Fixed charges; In situ; Luminescence; Minority carriers; Modulated photoluminescence; Photoluminescence; Photons; Plasma enhanced chemical vapor deposition; Silicon solar cells; Thin films; Silicon solar cells; Annealing; Modulated photoluminescence; In situ; Aluminum oxide; Fixed charges
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2021.111172

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. •Description of an in situ Modulated Photo-Luminescence acquisition tool.•Method for measuring the effective lifetime at an injection level of 1.1015 cm−3.•Description of kinetics of passivation of AlOx passivated samples upon annealing.•Observation of the combined action of temperature and light exposure.•Evidencing stable, high positive fixed charges in AlOx (1.1012 cm−2).