Ultra-high quality surface passivation of crystalline silicon wafers in large area parallel plate reactor at 40 MHz

• Published in: Thin solid films 2009-10, Vol.517 (23), p.6401-6404
• Main Authors: Damon-Lacoste, J., Fesquet, L., Olibet, S., Ballif, C.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Energy; Exact sciences and technology; Heterojunction; Ion and electron beam-assisted deposition; ion plating; Lifetime measurements; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Natural energy; Photovoltaic conversion; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma applications; Plasma processing and deposition; Plasma-based ion implantation and deposition; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2009.02.066

We use a new in-house, large area and automated deposition system: the usable deposition area is 410 × 520 mm with RF-frequency of 40 MHz. We deposit intrinsic a-Si:H layer on flat p-type or n-type c-Si wafers after performing an HF dip. The overall recombination of these double-side passivated c-Si wafers is measured with an effective lifetime measurement set-up. We pay particular attention to the uniformity of the passivation obtained on the whole deposition area. We point out a major role of hydrogen dilution on quality of c-Si passivation. Excellent uniformity is obtained on the whole area with implied open-circuit voltages ( V oc) in a ± 1.5% range. We achieve excellent passivation with overall lifetimes approaching 7 ms (at Δ n ≈ 4.5·10 14 cm − 3 ) resulting in implied V oc of 708 mV on p-type c-Si; and lifetimes superior to 4.7 ms resulting in implied V oc of 726 mV on n-type c-Si ( S eff less than 2 cm/s for both). These results open the way to very high efficiency heterojunction solar cell fabrication in large area reactors.