Passivation quality of a stoichiometric SiN_x single passivation layer on crystalline silicon prepared by catalytic chemical vapor deposition and successive annealing

Abstract

A silicon nitride (SiN x ) single passivation layer, prepared by catalytic chemical vapor deposition (Cat-CVD) and successive annealing, shows high passivation quality on crystalline silicon (c-Si) wafers. Effective minority carrier lifetime (τeff) monotonically increases with increase in deposition substrate temperature (T s) for samples passivated by as-deposited SiN x films, while more significant increase in τeff by annealing tends to be seen for the samples with SiN x films deposited at lower T s. The τeff obtained for the sample deposited at T s of 100 °C and pressure (P) of 10 Pa, after annealing at 350 °C for 30 min in N2, is about 3.0 ms, corresponding to a surface recombination velocity (SRV) of 5.0 cm/s. According to measured H content and fixed charge density (Q f) in the SiN x films, Q f partly contributes to the passivation quality of the films particularly before annealing, while H content plays an important role on improving passivation quality of the films after annealing.

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).…”

“…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.…”

“…[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. A Cat-CVD system can also be utilized to dope P or boron atoms to c-Si surfaces through the catalytic cracking of PH 3 or B 2 H 6 gas molecules.…”

Long-term stability of low-temperature deposited Cat-CVD SiN x thin film against damp-heat stress

“…In particular, Cat-CVD has many advantages, such as a high deposition rate, no plasma damage, low system cost, and large-scale film formation, which it makes a promising candidate to form SiN x films. Cat-CVD SiN x films exhibit a very good passivation property for c-Si solar cells, [14][15][16] and enhanced gas barrier properties for organic LED (OLED) devices and perovskite solar cells. 17,18) One of the important factors affecting the gas barrier ability of the SiN x film is its density.…”

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.…”