TY - JOUR
T1 - Passivation Enhancement of Poly-Si Carrier-Selective Contacts by Applying ALD Al_2O_3 Capping Layers
AU - Yang, Guangtao
AU - Van de Loo, Bas
AU - Stodolny, Maciej
AU - Limodio, Gianluca
AU - Melskens, Jimmy
AU - Isabella, Olindo
AU - Weeber, Arthur
AU - Zeman, Miro
AU - Kessels, W. M.M.
AU - More Authors, null
PY - 2021
Y1 - 2021
N2 - Hydrogenation of polycrystalline silicon (poly-Si) passivating contacts is crucial for maximizing their passivation performance. This work presents the application of Al2O3 prepared by atomic layer deposition as a hydrogenating capping layer. Several important questions related to this application of Al2O3 are addressed by comparing results from Al2O3 single layers, SiNx single layers, and Al2O3/SiNx double layers to different poly-Si types. We investigate the effect of the Al2O3 thickness, the poly-Si thickness, the poly-Si doping type, and the postdeposition annealing treatment on the passivation quality of poly-Si passivating contacts. Especially, the Al2O3/SiNx stack greatly enhances the passivation quality of both n+ and p+ doped as well as intrinsic poly-Si layers. The Al2O3 layer thickness is crucial for the single-layer approach, whereas the Al2O3/SiNx stack is less sensitive to the thickness of the Al2O3 layer. A thicker Al2O3 layer is needed for effectively hydrogenating p+ compared to n+ poly-Si passivating contact. The capping layers can hydrogenate poly-Si layers with thicknesses up to at least 600 nm. The hydrogenation-enhanced passivation for n+ poly-Si is found to be more thermally stable in comparison to p+ poly-Si. These results provide guidelines on the use of Al2O3 capping layers for poly-Si contacts to significantly improve their passivation performance.
AB - Hydrogenation of polycrystalline silicon (poly-Si) passivating contacts is crucial for maximizing their passivation performance. This work presents the application of Al2O3 prepared by atomic layer deposition as a hydrogenating capping layer. Several important questions related to this application of Al2O3 are addressed by comparing results from Al2O3 single layers, SiNx single layers, and Al2O3/SiNx double layers to different poly-Si types. We investigate the effect of the Al2O3 thickness, the poly-Si thickness, the poly-Si doping type, and the postdeposition annealing treatment on the passivation quality of poly-Si passivating contacts. Especially, the Al2O3/SiNx stack greatly enhances the passivation quality of both n+ and p+ doped as well as intrinsic poly-Si layers. The Al2O3 layer thickness is crucial for the single-layer approach, whereas the Al2O3/SiNx stack is less sensitive to the thickness of the Al2O3 layer. A thicker Al2O3 layer is needed for effectively hydrogenating p+ compared to n+ poly-Si passivating contact. The capping layers can hydrogenate poly-Si layers with thicknesses up to at least 600 nm. The hydrogenation-enhanced passivation for n+ poly-Si is found to be more thermally stable in comparison to p+ poly-Si. These results provide guidelines on the use of Al2O3 capping layers for poly-Si contacts to significantly improve their passivation performance.
KW - Atomic layer deposition (ALD) Al2O3
KW - hydrogenation
KW - passivation quality
KW - polycrystalline silicon (poly-Si) passivating contacts
KW - thermal stability
UR - http://www.scopus.com/inward/record.url?scp=85118583521&partnerID=8YFLogxK
U2 - 10.1109/JPHOTOV.2021.3119595
DO - 10.1109/JPHOTOV.2021.3119595
M3 - Article
AN - SCOPUS:85118583521
SN - 2156-3381
VL - 12
SP - 259
EP - 266
JO - IEEE Journal of Photovoltaics
JF - IEEE Journal of Photovoltaics
IS - 1
ER -