Doping profile measurement on textured silicon surface

Abstract

In crystalline silicon solar cells, the front surface is textured in order to lower the reflection of the incident light and increase the efficiency of the cell. This texturing whose dimensions are a few micrometers wide and high, often makes it difficult to determine the doping profile measurement. We have measured by secondary ion mass spectrometry (SIMS) and electrochemical capacitance voltage profiling the doping profile of implanted phosphorus in alkaline textured and in polished monocrystalline silicon wafers. The paper shows that SIMS gives accurate results provided the primary ion impact angle is small enough. Moreover, the comparison between these two techniques gives an estimation of the concentration of electrically inactive phosphorus atoms.

Best Performance of n<sup>+</sup> - p Crystalline Silicon Junction Solar Cells at 300 K, Due to the Effects of Heavy Doping and Impurity Size. I

“…1 μm = 10 . [ cm , decreases with increasing W, in good agreement with the doping profile measurement on silicon devices, studied by Essa et al [13]. Moreover, Equation (24) indicates that: (i) at the surface emitter: x=0, ρ(0) = N , defining the surface donor density, and (ii) at the emitter-base junction: x=W, ρ(W) = N (W) , which decreases with increasing W, as noted above.…”

“…Now, for g 6 , in d-Si systems at 300 K, our numerical ABGN ( ΔE )-results are calculated, using Equation (9). First, ours, obtained for the P-Si system, are plotted as a function of N in Figure 1 (a), in which, for a comparison, the other ones, calculated using Equations (10)(11)(12)(13)(14)(15), are also included. Secondly, in this P-Si system, the relative deviations between ours and the others are also plotted as functions of N in Figure 1 Here, one observes that: (i) our numerical ABGN-results obtained using Equations (9, 15) are found to be closed together as seen in Figure 1 (a), and their absolute maximal relative deviation yields: 3.03%, which occurs at N 1.2 9 10 C\ cm .W , as observed in Figure 1 (b), and (ii) in Figure 2 (c & , c C , for a given donor-Si system, due to the heavy doping effect, ours increase with increasing N, and for a given N, ours increase ( §) with increasing r * , due to the donor-size effect.…”

“…I expressed as functions of the open circuit voltage V [4]. Further, it should be noted that, in most fabricated silicon devices, the effective Gaussian donor-density profile ρ x , being proposed in next Equation (24), varies with carrier position x in the emitter region of width W [13,[18][19][20]22], and it decreases with increasing W, being found to be in good agreement with that used by Essa et al [13]. As a result, many other physical quantities, given in this NUHD n(p)-type thin emitter region such as : the band gap narrowing (BGN), ΔE , Fermi energy E , apparent band gap narrowing (ABGN), ΔE , minority-hole (electron) mobility μ , minority-hole (electron) lifetime τ , and minority-hole (electron) diffusion length L , strongly depend on ρ x .…”

31.474 (44.359) %- Limiting Highest Efficiencies obtained in the \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{n}^+(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{p}^+)-\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{p}(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{n})\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ Crystalline GaAs Junction Solar Cells at T=300 K, Due to The Effects of Heavy (L

“…In our recent works [1,2], by basing on: (i) the heavy doping and impurity size effects, which affect the total carrier-minority saturation current density J oI(II) ≡ J En(p)o + J Bp(n)o , where those J En(p)o (J Bp(n)o ) are injected respectively into the heavily doped donor (acceptor)-Si emitterlightly doped acceptor (donor)-GaAs base-regions, HD[d(a)-Si]ER-LD[a(d)-Si]BR, of the n + (p + ) − p(n) junction solar cells, denoted by I(II), respectively, (ii) an effective Gaussian donor (acceptor)-density profile ρ d(a) to determine J En(p)o [1,2,13,[18][19][20]22] and (iii) the use of two fixed experimental points, we investigated the photovoltaic conversion factor n I(II) , the short circuit current density J scI(II) , the fill factor F I(II) , and finally the efficiency η I(II) . These Further, we remark [1,2] that: (a) for a given V oc , both n I(II) and J oI(II) have the same variations and strongly affect other ( J scI(II) , F I(II) , η I(II) )-results, and (b) for a given V oc , and with decreasing S and increasing W, while both n I(II) and J oI(II) decrease from the completely transparent emitter region (CTER), as S → ∞ , to the completely opaque emitter-region (COER), as S → 0, J scI(II) , F I(II) , and η I(II) therefore increase from the CTER-case to the COER-one.…”

33.01% (31.06%)- Limiting Highest Efficiencies obtained in \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{n}^+(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{p}^+)-\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{p}(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\mathbf{n})\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ Crystalline Silicon Junction Solar Cells at T=300 K, Due to The Effects of Heavy (Low)

“…In our recent works [1,2], which will be henceforth referred to as I and II, by basing on: (i) the heavy doping and impurity size effects, which affect the total carrier-minority saturation current density J oI(II) ≡ J En(p)o + J Bp(n)o , where those J En(p)o (J Bp(n)o ) are injected respectively into the heavily doped donor (acceptor)-Si emitter-lightly doped acceptor (donor)-Si base-regions, HD[d(a)-Si]ER-LD[a(d)-Si]BR, of n + (p + ) − p(n) junction solar cells, (ii) an effective Gaussian donor (acceptor)-density profile ρ d(a) to determine J En(p)o [1,2,13,[18][19][20]22] and (iii) the use of two fixed experimental points, we investigated the photovoltaic conversion factor n I(II) , the short circuit current density J scI(II) , the fill factor F I(II) , and finally the efficiency η I(II) [1,45]. These physical quantities were expressed as functions of the open circuit voltage V oc , and various parameters such as: the emitter thickness W , high donor (acceptor) density N d(a) , surface recombination velocity S , given in the HD[d(a)-Si]ER, and low acceptor (donor) density N a(d) , in the LD[a(d)-Si]BR.…”