Electrical and chemical studies on Al2O3 passivation activation process - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2014

Electrical and chemical studies on Al2O3 passivation activation process

Résumé

Passivation process is a key feature to improve the efficiency of silicon solar cells. So far, a 20nm-thick layer of Al2O3 grown by Plasma Enhanced Atomic Layer Deposition (PE-ALD) followed by a 450°C anneal during 15 to 30 min gives the best results in surface carrier recombination velocities on p-type silicon. In this study we used chemical (XPS profiling, SIMS), and electrical (C-V, QSS-PCD) characterisation to obtain a better understanding of the passivation activation process. A 20nm-thick Al2O3 film is deposited on 200µm Cz p-type c-Si (100) wafers with a resistivity of 5Ω.cm by PE-ALD. Starting from as-deposited state to anneal time up to 1 hour, the evolution of chemicals components at the interface Al2O3/Si is recorded in conjunction with macroscopic parameters (Density of effectives charges (Qeff), Density of interface defects (Dit) and carrier lifetime). First XPS analyses show that the SiO2 interface layer is not the driving parameter of a good passivation since it is not affected by annealing. However chemical bonds, such as Al-O-Si appear as the sample is annealed. At the same time, SIMS measurements confirm an outgassing of hydrogen, contained in the Al2O3 layer, toward the silicon during the thermal treatment with a maximum penetration depth into the silicon at 30 min of annealing. This evolution is in good agreement with the electrical values, deduced from the C(V) measurements, where the Dit at 30min is low (109 cm-3) and the Qeff is high (-1.1013 cm-3).
Fichier non déposé

Dates et versions

hal-00964247 , version 1 (24-03-2014)

Identifiants

  • HAL Id : hal-00964247 , version 1

Citer

Matthieu Pawlik, Jean-Pierre Vilcot, Mathieu Halbwax, D. Aureau, A. Etcheberry, et al.. Electrical and chemical studies on Al2O3 passivation activation process. European Materials Research Society Spring Meeting, E-MRS Spring 2014, Symposium Y - Advanced materials and characterization techniques for solar cells II, 2014, Lille, France. ⟨hal-00964247⟩
141 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More