Lossen, J.; Hoß, J.; Eisert, S.; Amkreutz, D.; Muske, M.; Plantz, J.; Andrä, G.: Electron Beam Evaporation of Silicon for Poly-Silicon/SiO2 Passivated Contacts. In: Proceedings : EU PVSEC 2018, 35th European Photovoltaic Solar Energy Conference and Exhibition : 24-28 September 2018, SQUARE - Brussels Meeting Centre, Brussels, Belgium. EUPVCEC, 2018. - ISBN 3-936338-50-7, p. 418-421
We assess the use of electron-beam physical vapor deposition (EB-PVD) for the deposition of silicon layers to be used in doped poly-Si/SiO2 passivated carrier selective contacts. It is shown that the crystallinity of the deposited layer can be tuned by the substrate temperature. Nano crystalline (nc-Si) intrinsic layers deposited at substantially different deposition rates of 25 nm/min and 500 nm/min show similar doping profiles after an ex-situ doping by POCl3 diffusion and similar passivation quality with iVoc > 715 mV for symmetrical lifetime samples on a n-type substrate. Best passivation characteristics with iVoc of 732 mV and J0e of 3 fA/cm2 are achieved for in-situ doped layers with an active phosphorous concentration of [P] = 2*1020cm-3 after annealing. A low sheet resistance of 142 Ω/sq for a 100 nm thick layer make this stack eligible for ready integration into a screen printed solar cell. While layer properties are shown to be similar to those of parallel processed LPCVD layers, the single sided deposition characteristic EB-PVD constitutes a significant advantage for easy integration of the process step into a lean industrial process flow.