Ultra high-rate ETP deposited silicon nitride for <15% in-line processed multicrystalline silicon solar cells

Abstract

The DEPx ,developed by OTB Solar, uses the ETP technique for the deposition of a silicon nitride ARC on silicon solar cells. With this technique very high deposition rates can be achieved and experiments were carried out with Shell Solar to investigate the quality of these ultra high-rate deposited silicon nitride layers. An optimization study which focused on mass density and thermal stability showed that mc-Si solar cell efficiencies of >15% can be reached with silicon nitride grown at >5 nmls.

The effect of composition on the bond structure and refractive index of silicon nitride deposited by HWCVD and PECVD

“…The position of the FTIR Si-H stretching mode Fig. 4 shows the Si-H peak position for the present SiN x films along with data found in literature [13][14][15][16][17]. For films with an N/Si ratio larger than 0.6, the Si-H peak positions are similar, for films with an N/Si ratio smaller than 0.6 discrepancies appear.…”

Industrial high-rate (∼5 nm/s) deposited silicon nitride yielding high-quality bulk and surface passivation under optimum anti-reflection coating conditions

“…In Figure 2 the efficiency of the solar cells is shown for the high-mass-density a-SiN x :H films deposited at deposition temperatures in the range of 300-425 C. This figure shows that efficiencies up to 15Á3% have been obtained (as averaged over 10 solar cells) when a-SiN x :H with a mass density of 2Á45 g/cm 3 is used. 17 These solar cells results show that the very high-rate deposited a-SiN x :H films can compete with lowrate (<<1 nm/s) a-SiN x :H films yielding a top solar cell efficiency of 15Á5% in a reference experiment. Furthermore, Figure 2 again confirms our previous proposition that high mass densities are essential for obtaining a high level of bulk passivation and, therefore, for obtaining high-efficiency multicrystalline silicon solar cells.…”

“…Efficiency of multicrystalline silicon solar cells (averaged over 10 cells) as a function of the mass density of the a-SiN x :H antireflection coating. 17 The mass density of the a-SiN x :H films, measured by Rutherford backscattering analysis, is varied by the changing the deposition temperature of the solar cells from 300 to 425 C. The thickness of the films was tuned such that the reflectivity of the solar cells was minimized for small changes in refractive index a-SiN x :H films with a refractive index ranging from 1Á9 to 2Á7, obtained by changing the NH 3 /SiH 4 ratio in the plasma. The refractive index as well as the absorption coefficient and film thickness were determined by means of spectroscopic ellipsometry (Woollam M2000) over a photon energy range of 0Á7-5Á0 eV.…”

Quantifying optical loss of high‐voltage degradation modes in photovoltaic modules using spectral analysis

“…Hydrolysis of Si x N y films in subcritical and supercritical water was separately found to produce water‐soluble forms of silica and ammonia [41, 42]. Changes in appearance and optical properties may also result from changes in composition (e.g., stoichiometry) of the Si x N y layer [45]. The thickness of an Si x N y film on Si can be assessed from its color [43].…”