Single Sided High Throughput Sputter Process Technology for In-Situ Doped n-Type Amorphous Silicon Layers for High Efficiency TOPCon Solar Cells
- Resource Type
- Authors
- Linss, V.; Dietsch, T.; Baumann, J.; Graupner, U.; Hoß, J.; Linke, J.; Lossen, J.; Polzin, J.I.; Mack, S.; Nagel, H.; Bivour, M.; Schneiderlöchner, E.
- Source
- Subject
- Manufacturing & Production of Si Cells
Silicon Materials and Cells
- Language
- English
8th World Conference on Photovoltaic Energy Conversion; 202-207
In this work we report on the development of an industrially relevant in-situ doped sputtering process for depositing 100-150 nm thick aSi(n) layers to passivate the rear contact of TOPCon solar cells. All relevant properties of the poly-Si layers have been optimized using symmetrical lifetime samples. The sputtered aSi(n) layers do not show blistering effects and can be doped with Phosphorus concentrations larger than 1E21 at/cm³ which has been evaluated via calibrated SIMS measurements. ECV measurements of optimized layers after a high temperature anneal at 850-980 °C for 10-30 min confirm the necessary electrically active concentration cP ~ 1-3E20 at/cm³. After tuning the interfacial oxide layer and optimizing the PVD process parameters as well as the annealing process implied open circuit voltages iVoc > 735 mV could be measured on symmetrical lifetime structures at one sun injection density on 1-3 Ωcm n-type Cz-wafers. Corresponding sheet resistances of the 140 nm thick poly-Si layers range from 60-320 Ω/sq and sufficiently low specific contact resistivities below 10 mΩcm² for screen-printed contacts have been determined accompanied by low recombination of J0,met < 65 fA/cm². The best TOPCon solar cell with sputtered poly-Si layers has an efficiency of 23.4 % measured by ISE CalLab PV Cells.