Power density in RF PECVD: a factor for deposition of amorphous silicon thin films and successive solid phase crystallization

Das, Chandan; Ray, Swati

doi:10.1088/0022-3727/35/17/319

Cited by 13 publications

(4 citation statements)

References 25 publications

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“…This causes a decrease in the surface roughness with the result that the crystalline volume fraction increases as shown in figure 6. Our observation agrees well with that of Fujiwara et al [13,14] for microcrystalline films.…”

Section: Resultssupporting

confidence: 93%

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH₄/H₂gases: microstructural characterization

Chen¹,

Qiu²,

Liu³

et al. 2008

J. Phys. D: Appl. Phys.

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Hydrogenated nanocrystalline silicon thin films were deposited at a high rate of 0.8 nm s−1 by conventional (13.56 MHz) plasma enhanced chemical vapour deposition from SHi4/H2 gas mixture at a low temperature of 200 °C. The effects of hydrogen dilution, radio frequency power density, substrate temperature and deposition pressure on the crystalline volume fraction and the deposition rate of films were systematically investigated. The results show that the high hydrogen dilution and the substrate temperature are favourable for improving the crystallinity properties. The high deposition rate requires high power density over 0.7 W cm−2 in combination with high deposition pressure above several hundreds of Pa to overcome the degradation of film quality.

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Section: Resultssupporting

confidence: 93%

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH₄/H₂gases: microstructural characterization

Chen¹,

Qiu²,

Liu³

et al. 2008

J. Phys. D: Appl. Phys.

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“…A similar trend also indicates that an increase in hydrogen dilution ratio (R) also boosts the density of atomic H in the deposition chamber and further enhances the surface diffusion with a hydrogenaccumulated growing surface [42]. Both the synergetic effect of the hydrogen etching effect [43] and amorphous-to-nanocrystalline transition can be observed in a hydrogen dilution ratio (R) range of 30-40, which is in agreement with the Raman shift in Figure 4. Figure 8a shows a series of OES of RF glow discharges of Hα*/SiH* and Si*/SiH* with a different dilution ratio (R).…”

Section: Fourier Transform Infra-red (Ftir) Spectroscopy Analysissupporting

confidence: 83%

In Situ Plasma Monitoring of PECVD nc-Si:H Films and the Influence of Dilution Ratio on Structural Evolution

et al. 2018

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We report plasma-enhanced chemical vapor deposition (PECVD) hydrogenated nano-crystalline silicon (nc-Si:H) thin films. In particular, the effect of hydrogen dilution ratio (R = H 2 /SiH 4) on structural and optical evolutions of the deposited nc-Si:H films were systematically investigated including Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and low angle X-ray diffraction spectroscopy (XRD). Measurement results revealed that the nc-Si:H structural evolution, primarily the transition of nano-crystallization from the amorphous state to the nanocrystalline state, can be carefully induced by the adjustment of hydrogen dilution ratio (R). In addition, an in situ plasma diagnostic tool of optical emission spectroscopy (OES) was used to further characterize the crystallization rate index (H α */SiH*) that increases when hydrogen dilution ratio (R) rises, whereas the deposition rate decreases. Another in situ plasma diagnostic tool of quadruple mass spectrometry (QMS) also confirmed that the "optimal" range of hydrogen dilution ratio (R = 30-40) can yield nano-crystalline silicon (n-Si:H) growth due to the depletion of higher silane radicals. A good correlation between the plasma characteristics by in situ OES/QMS and the film characteristics by XRD, Raman and FTIR, for the transition of a-Si:H to nc-Si:H film from the hydrogen dilution ratio, was obtained.

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“…Thus, Ns increase with increasing PW in the nanocrystalline silicon films. A similar dependence of the spin density of a-Si:H on power density has been reported elsewhere [26].…”

Section: Scanning Electron Microscopysupporting

confidence: 84%

Three Generations of Solar Cells

Goswami¹

2021

AMR

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In photovoltaic system the major challenge is the cost reduction of the solar cell module to compete with those of conventional energy sources. Evolution of solar photovoltaic comprises of several generations through the last sixty years. The first generation solar cells were based on single crystal silicon and bulk polycrystalline Si wafers. The single crystal silicon solar cell has high material cost and the fabrication also requires very high energy. The second generation solar cells were based on thin film fabrication technology. Due to low temperature manufacturing process and less material requirement, remarkable cost reduction was achieved in these solar cells. Among all the thin film technologies amorphous silicon thin film solar cell is in most advanced stage of development and is commercially available. However, an inherent problem of light induced degradation in amorphous silicon hinders the higher efficiency in this kind of cell. The third generation silicon solar cells are based on nano-crystalline and nano-porous materials. Hydrogenated nanocrystalline silicon (nc-Si:H) is becoming a promising material as an absorber layer of solar cell due to its high stability with high Voc. It is also suggested that the cause of high stability and less degradation of certain nc-Si:H films may be due to the improvement of medium range order (MRO) of the films. During the last ten years, organic, polymer, dye sensitized and perovskites materials are also attract much attention of the photovoltaic researchers as the low budget next generation PV material worldwide. Although most important challenge for those organic solar cells in practical applications is the stability issue. In this work nc-Si:H films are successfully deposited at a high deposition rate using a high pressure and a high power by Radio Frequency Plasma Enhanced Chemical Vapor Deposition (RF PECVD) technique. The transmission electron microscopy (TEM) studies show the formations of distinct nano-sized grains in the amorphous tissue with sharp crystalline orientations. Light induced degradation of photoconductivity of nc-Si:H materials have been studied. Single junction solar cells and solar module were successfully fabricated using nanocrystalline silicon as absorber layer. The optimum cell is 7.1 % efficient initially. Improvement in efficiency can be achieved by optimizing the doped layer/interface and using Ag back contact.

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Power density in RF PECVD: a factor for deposition of amorphous silicon thin films and successive solid phase crystallization

Cited by 13 publications

References 25 publications

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH₄/H₂gases: microstructural characterization

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH₄/H₂gases: microstructural characterization

In Situ Plasma Monitoring of PECVD nc-Si:H Films and the Influence of Dilution Ratio on Structural Evolution

Three Generations of Solar Cells

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Power density in RF PECVD: a factor for deposition of amorphous silicon thin films and successive solid phase crystallization

Cited by 13 publications

References 25 publications

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH4/H2gases: microstructural characterization

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH4/H2gases: microstructural characterization

In Situ Plasma Monitoring of PECVD nc-Si:H Films and the Influence of Dilution Ratio on Structural Evolution

Three Generations of Solar Cells

Contact Info

Product

Resources

About

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH₄/H₂gases: microstructural characterization

Low temperature fast growth of nanocrystalline silicon films by rf-PECVD from SiH₄/H₂gases: microstructural characterization