A series of microcrystalline silicon thin films were fabricated by very high frequency plasma enhanced chemical vapor deposition （VHF-PECVD） at different silane concentrations in a P chamber. Through analysis of the...A series of microcrystalline silicon thin films were fabricated by very high frequency plasma enhanced chemical vapor deposition （VHF-PECVD） at different silane concentrations in a P chamber. Through analysis of the structural and electrical properties of these materials,we conclude that the photosensitivity slightly decreased then increased as the silane concentration increased,while the crystalline volume fraction indicates the opposite change. Results of XRD indicate that thin films have a （220） preferable orientation under certain conditions. Microcrystalline silicon solar cells with conversion efficiency 4. 7% and micromorph tandem solar cells 8.5% were fabricated by VHF-PECVD （p layer and i layer of microcrystalline silicon solar cells were deposited in P chamber）, respectively.展开更多
Amorphous silicon nitride films were deposited by low-frequency plasma-enhanced chemical vapor deposition（LF-PECVD） using silane and nitrogen as precursors. Characteristics such as deposition rate, surface morpholog...Amorphous silicon nitride films were deposited by low-frequency plasma-enhanced chemical vapor deposition（LF-PECVD） using silane and nitrogen as precursors. Characteristics such as deposition rate, surface morphology, and chemical composition were measured by spectroscopic ellipsometry（SE）, atomic force mieroscope（AFM） and x-ray photoelectron spectroscopy（XPS）. It was shown that amorphous silicon nitride film could be prepared by LF-PECVD with good uniformity and even surface. The XPS result indicated that a small quantity of oxygen was involved in the sample, which was discussed in this paper.展开更多
We present a numerical gas phase reaction model for hydrogenated microcrystalline silicon(μc-Si:H) films from SiH4 and H2 gas mixtures with plasma enhanced chemical vapor deposition(PECVD).Under the typical μc-Si:H ...We present a numerical gas phase reaction model for hydrogenated microcrystalline silicon(μc-Si:H) films from SiH4 and H2 gas mixtures with plasma enhanced chemical vapor deposition(PECVD).Under the typical μc-Si:H deposition conditions,the concentrations of the species in the plasma are calculated and the effects of silane fraction(SF=[SiH4]/[H2+SiH4]) are investigated.The results show that SiH3 is the key precursor for μc-Si:H films growth,and other neutral radicals,such as Si2H5,Si2H4 and SiH2,may play some roles in the film deposition.With the silane fraction increasing,the precursor concentration increases,but H atom concentration decreases rapidly,which results in the lower H/SiH3 ratio.展开更多
In this paper, we tion （SHJ） solar cells with prepared silicon heterojunc- the structure of p-c-Si/i-a- SiOx：H/n-μc-SiOx：H （a-SiOx：H, oxygen rich amorphous silicon oxide; μc-SiOx：H, microcrystalline silicon o...In this paper, we tion （SHJ） solar cells with prepared silicon heterojunc- the structure of p-c-Si/i-a- SiOx：H/n-μc-SiOx：H （a-SiOx：H, oxygen rich amorphous silicon oxide; μc-SiOx：H, microcrystalline silicon oxide） by plasma-enhanced chemical vapor deposition method. The influence of the n-μc-SiOx：H emitter thickness on the heterointerface passivation in SHJ solar cells was investi- gated. With increasing thickness, the crystallinity of the emitter as well as its dark conductivity increases. Mean- while, the effective minority carrier lifetime （teff） of the SHJ solar cell precursors at low injection level shows a pronounced increase trend, implying that an improved field effect passivation is introduced as the emitter is deposited. And, an increased μTelf is also observed at entire injection level due to the interfacial chemical passivation improved by the hydrogen diffusion along with the emitter deposition. Based on the analysis on the external quantum effi- ciency of the SHJ solar cells, it can be expected that the high efficient SHJ solar cells could be obtained by improving the heterointerface passivation and optimizing the emitter deposition process.展开更多
A series of hydrogenated microcrystalline silicon （μc-Si：H） p-layers for back surface field in crystalline silicon solar cells were deposited on glass substrates by the developed large area （45 cm×45 cm） pl...A series of hydrogenated microcrystalline silicon （μc-Si：H） p-layers for back surface field in crystalline silicon solar cells were deposited on glass substrates by the developed large area （45 cm×45 cm） plasma enhanced chemical vapour deposition processor operating at 13.56 MHz and various values of source gas trimethylboron （TMB） to H2 flowratio. The influence of deposition parameters on the large area p-layer performance was intensively studied, as well as the thin film uniformity, optical, electrical and structural performances by Raman, PTIR, Ellipsometry, etc. Arrhenius and Tauc plots were used to discuss the μc-Si：H thin film＇s activation energy and the defects state distribution. When amorphous-microcrystalline transition state was obtained, the deposited p-doped μc-Si：H layers showed specific resistance of 38.3 Ω^-1cm1 at the flowratio of 0.66% and high crystallinity of 45%-50% with no further treatment. The effect of source gas flowratio, deposition rate, and source gas partial pressure on μc-Si：H thin film＇s performance was also investigated.展开更多
Stress controllable silicon nitride(Si Nx) films deposited by plasma enhanced chemical vapor deposition(PECVD) are reported. Low stress Si Nx films were deposited in both high frequency(HF) mode and dual frequency(HF/...Stress controllable silicon nitride(Si Nx) films deposited by plasma enhanced chemical vapor deposition(PECVD) are reported. Low stress Si Nx films were deposited in both high frequency(HF) mode and dual frequency(HF/LF) mode. By optimizing process parameters, stress free(-0.27 MPa) Si Nx films were obtained with the deposition rate of 45.5 nm/min and the refractive index of 2.06. Furthermore, at HF/LF mode, the stress is significantly influenced by LF ratio and LF power, and can be controlled to be 10 MPa with the LF ratio of 17% and LF power of 150 W. However, LF power has a little effect on the deposition rate due to the interaction between HF power and LF power. The deposited Si Nx films have good mechanical and optical properties, low deposition temperature and controllable stress, and can be widely used in integrated circuit(IC), micro-electro-mechanical systems(MEMS) and bio-MEMS.展开更多
文摘A series of microcrystalline silicon thin films were fabricated by very high frequency plasma enhanced chemical vapor deposition （VHF-PECVD） at different silane concentrations in a P chamber. Through analysis of the structural and electrical properties of these materials,we conclude that the photosensitivity slightly decreased then increased as the silane concentration increased,while the crystalline volume fraction indicates the opposite change. Results of XRD indicate that thin films have a （220） preferable orientation under certain conditions. Microcrystalline silicon solar cells with conversion efficiency 4. 7% and micromorph tandem solar cells 8.5% were fabricated by VHF-PECVD （p layer and i layer of microcrystalline silicon solar cells were deposited in P chamber）, respectively.
文摘Amorphous silicon nitride films were deposited by low-frequency plasma-enhanced chemical vapor deposition（LF-PECVD） using silane and nitrogen as precursors. Characteristics such as deposition rate, surface morphology, and chemical composition were measured by spectroscopic ellipsometry（SE）, atomic force mieroscope（AFM） and x-ray photoelectron spectroscopy（XPS）. It was shown that amorphous silicon nitride film could be prepared by LF-PECVD with good uniformity and even surface. The XPS result indicated that a small quantity of oxygen was involved in the sample, which was discussed in this paper.
基金supported by the State Key Development Program for Basic Research of China (No.2006CB202601)the National Natural Science Foundation of China (No.51007082)the Natural Science Foundation of Henan Province (No.072300410080)
文摘We present a numerical gas phase reaction model for hydrogenated microcrystalline silicon(μc-Si:H) films from SiH4 and H2 gas mixtures with plasma enhanced chemical vapor deposition(PECVD).Under the typical μc-Si:H deposition conditions,the concentrations of the species in the plasma are calculated and the effects of silane fraction(SF=[SiH4]/[H2+SiH4]) are investigated.The results show that SiH3 is the key precursor for μc-Si:H films growth,and other neutral radicals,such as Si2H5,Si2H4 and SiH2,may play some roles in the film deposition.With the silane fraction increasing,the precursor concentration increases,but H atom concentration decreases rapidly,which results in the lower H/SiH3 ratio.
文摘In this paper, we tion （SHJ） solar cells with prepared silicon heterojunc- the structure of p-c-Si/i-a- SiOx：H/n-μc-SiOx：H （a-SiOx：H, oxygen rich amorphous silicon oxide; μc-SiOx：H, microcrystalline silicon oxide） by plasma-enhanced chemical vapor deposition method. The influence of the n-μc-SiOx：H emitter thickness on the heterointerface passivation in SHJ solar cells was investi- gated. With increasing thickness, the crystallinity of the emitter as well as its dark conductivity increases. Mean- while, the effective minority carrier lifetime （teff） of the SHJ solar cell precursors at low injection level shows a pronounced increase trend, implying that an improved field effect passivation is introduced as the emitter is deposited. And, an increased μTelf is also observed at entire injection level due to the interfacial chemical passivation improved by the hydrogen diffusion along with the emitter deposition. Based on the analysis on the external quantum effi- ciency of the SHJ solar cells, it can be expected that the high efficient SHJ solar cells could be obtained by improving the heterointerface passivation and optimizing the emitter deposition process.
基金supported by the National "863" Project of China (Grant No.2006AA05Z409)the "Kaisi" Oversea R&D Schol-arship of Sun Yat-sen University
文摘A series of hydrogenated microcrystalline silicon （μc-Si：H） p-layers for back surface field in crystalline silicon solar cells were deposited on glass substrates by the developed large area （45 cm×45 cm） plasma enhanced chemical vapour deposition processor operating at 13.56 MHz and various values of source gas trimethylboron （TMB） to H2 flowratio. The influence of deposition parameters on the large area p-layer performance was intensively studied, as well as the thin film uniformity, optical, electrical and structural performances by Raman, PTIR, Ellipsometry, etc. Arrhenius and Tauc plots were used to discuss the μc-Si：H thin film＇s activation energy and the defects state distribution. When amorphous-microcrystalline transition state was obtained, the deposited p-doped μc-Si：H layers showed specific resistance of 38.3 Ω^-1cm1 at the flowratio of 0.66% and high crystallinity of 45%-50% with no further treatment. The effect of source gas flowratio, deposition rate, and source gas partial pressure on μc-Si：H thin film＇s performance was also investigated.
基金supported by the National High Technology Research and Development Program of China(No.2015AA042603)the Fundamental Research Funds for the Central Universities of China(No.106112014CDJZR160001)
文摘Stress controllable silicon nitride(Si Nx) films deposited by plasma enhanced chemical vapor deposition(PECVD) are reported. Low stress Si Nx films were deposited in both high frequency(HF) mode and dual frequency(HF/LF) mode. By optimizing process parameters, stress free(-0.27 MPa) Si Nx films were obtained with the deposition rate of 45.5 nm/min and the refractive index of 2.06. Furthermore, at HF/LF mode, the stress is significantly influenced by LF ratio and LF power, and can be controlled to be 10 MPa with the LF ratio of 17% and LF power of 150 W. However, LF power has a little effect on the deposition rate due to the interaction between HF power and LF power. The deposited Si Nx films have good mechanical and optical properties, low deposition temperature and controllable stress, and can be widely used in integrated circuit(IC), micro-electro-mechanical systems(MEMS) and bio-MEMS.
