Impact of PECVD μc-Si:H deposition on tunnel oxide for passivating contacts
EDF R&D, Bvd Gaspard Monge, 91120 Palaiseau, France
2 Institut Photovoltaïque d'Ile-de-France (IPVF), 18 Bvd Thomas Gobert, 91120 Palaiseau, France
3 LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128 Palaiseau, France
4 Photowatt, EDF ENR PWT, 33 rue Saint-Honoré, Z.I. Champfleuri, 38300 Bourgoin-Jallieu, France
5 ILV, Université de Versailles Saint-Quentin en Yvelines, Université Paris-Saclay, CNRS, 78035 Versailles, France
6 TOTAL GRP, 2 Place Jean Millier − La Défense 6, 92078 Paris La Défense Cedex, France
* e-mail: firstname.lastname@example.org
Received in final form: 16 December 2019
Accepted: 6 January 2020
Published online: 4 February 2020
Passivating contacts are becoming a mainstream option in current photovoltaic industry due to their ability to provide an outstanding surface passivation along with a good conductivity for carrier collection. However, their integration usually requires long annealing steps which are not desirable in industry. In this work we study PECVD as a way to carry out all deposition steps: silicon oxide (SiOx), doped polycrystalline silicon (poly-Si) and silicon nitride (SiNx:H), followed by a single firing step. Blistering of the poly-Si layer has been avoided by depositing (p+) microcrystalline silicon (μc-Si:H). We report on the impact of this deposition step on the SiOx layer deposited by PECVD, and on the passivation properties by comparing PECVD and wet-chemical oxide in this hole-selective passivating contact stack. We have reached iVoc > 690 mV on p-type FZ wafers for wet-chemical SiOx\(p+) μc-Si\SiNx:H with no annealing step.
Key words: Silicon solar cell / passivating contact / silicon oxide / μc-Si:H / PECVD / XPS / passivation / cast-mono
© A. Desthieux et al., published by EDP Sciences, 2020
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