Defect termination on crystalline silicon surfaces by hydrogen for improvement in the passivation quality of catalytic chemical vapor-deposited SiN_x and SiN_x/P catalytic-doped layers

Abstract

We investigate the role of hydrogen (H) in the improvement in the passivation quality of silicon nitride (SiN x ) prepared by catalytic chemical vapor deposition (Cat-CVD) and Cat-CVD SiN x /phosphorus (P) Cat-doped layers on crystalline silicon (c-Si) by annealing. Both structures show promising passivation capabilities for c-Si with extremely low surface recombination velocity (SRV) on n-type c-Si. Defect termination by H is evaluated on the basis of defect density (N d) determined by electron spin resonance (ESR) spectroscopy and interface state density (D it) calculated by the Terman method. The two parameters are found to be drastically decreased by annealing after SiN x deposition. The calculated average D it at midgap (D it-average) is 2.2 × 1011 eV−1 cm−2 for the SiN x /P Cat-doped c-Si sample with a SRV of 2 cm/s, which is equivalent to 3.1 × 1011 eV−1 cm−2 for the SiN x /c-Si sample with a SRV of 5 cm/s after annealing. The results indicate that H atoms play a critical role in the reduction in D it for SiN x /c-Si and SiN x /P Cat-doped c-Si, resulting in a drastic reduction in SRV by annealing.

In Situ Copper Coating on Silicon Particles Enables Long Durable Anodes in Lithium-Ion Batteries

“…The process of synthesizing HT-Si@Cu is illustrated in Figure . After the treatment of nanosized silicon particles (named n-Si) with dilute hydrofluoric acid, reactive hydrogenated silicon (named n-Si–H) on the particle surface was generated. , Upon the addition of copper citrate, Cu 2+ was immediately reduced and transformed to spherical Cu particles that were tightly enwrapped on the surface of silicon. To further strengthen the connection between Si and Cu, the Si@Cu composite underwent heat treatment at 800 °C in an Ar/H 2 mixed atmosphere to obtain the product HT-Si@Cu.…”

Passivation of textured crystalline silicon surfaces by catalytic CVD silicon nitride films and catalytic phosphorus doping

“…29,30) The samples with SiN x films were then annealed at 350 °C for 30 min under N 2 atmosphere in a tube furnace to enhance the termination of dangling bonds on c-Si surfaces by hydrogen atoms supplied from SiN x films for improvement in passivation quality. 12,16) After the postannealing, the SiN x films show a fixed charge density of 7 × 10 11 =cm 2 and an interface state density of 3.1 × 10 11 =cm 2 . 16) The surface morphology of the textured c-Si wafers was observed by scanning electron microscopy (SEM).…”

“…12,16) After the postannealing, the SiN x films show a fixed charge density of 7 × 10 11 =cm 2 and an interface state density of 3.1 × 10 11 =cm 2 . 16) The surface morphology of the textured c-Si wafers was observed by scanning electron microscopy (SEM). The optical reflectance spectra of uncoated and SiN x -coated c-Si wafers before and after texturing were measured in a spectrophotometer (Shimadzu UV-3150) equipped with an integrating sphere.…”

“…Owing to this feature, Cat-CVD can realize the plasma-damage-less deposition of thin films such as a-Si and Si nitride (SiN x ), and produce high-quality films for the passivation of c-Si surfaces. [8][9][10][11][12][13][14][15][16] We have thus far realized Cat-CVD SiN x passivation films showing a surface recombination velocity (SRV) of ∼5 cm=s on mirror-polished c-Si(100) surfaces. 12) It should be emphasized that the SiN x films are stoichiometric and have a refractive index of ∼2, leading to no parasitic absorption of sunlight.…”

Passivation effect of ultra-thin SiN x films formed by catalytic chemical vapor deposition for crystalline silicon surface

“…16,17) Cat-CVD can realize low-damage deposition of passivation films due to its plasma-damage-less nature, and we have thus far demonstrated high-quality passivation films formed by Cat-CVD. [18][19][20][21][22][23][24] In this study, we attempt to form ultra-thin SiN x films aiming at the utilization of the SiN x as the substitute of tunneling SiO 2 in the TOPCon structure.…”