共查询到20条相似文献,搜索用时 46 毫秒
1.
Keisuke Ohdaira Kazuhiro Shiba Hiroyuki Takemoto Tomoko Fujiwara Yohei Endo Shogo Nishizaki Young Rae Jang Hideki Matsumura 《Thin solid films》2009,517(12):3472-4461
Amorphous Si (a-Si) films with lower hydrogen contents show better adhesion to glass during flash lamp annealing (FLA). The 2.0 µm-thick a-Si films deposited by plasma-enhanced chemical vapor deposition (PECVD), containing 10% hydrogen, start to peel off even at a lamp irradiance lower than that required for crystallization, whereas a-Si films deposited by catalytic CVD (Cat-CVD) partially adhere even after crystallization. Dehydrogenated Cat-CVD a-Si films show much better adhesion to glass, and are converted to polycrystalline Si (poly-Si) without serious peeling, but are accompanied by the generation of crack-like structures. These facts demonstrate the superiority of as-deposited Cat-CVD a-Si films as a precursor material for micrometer-thick poly-Si formed by FLA. 相似文献
2.
Yohei Endo Keisuke Ohdaira Shogo Nishizaki Hideki Matsumura 《Thin solid films》2010,518(17):5003-2839
We have fabricated thin-film solar cells using polycrystalline silicon (poly-Si) films formed by flash lamp annealing (FLA) of 4.5-µm-thick amorphous Si (a-Si) films deposited on Cr-coated glass substrates. High-pressure water-vapor annealing (HPWVA) is effective to improve the minority carrier lifetime of poly-Si films up to 10 µs long. Diode and solar cell characteristics can be seen only in the solar cells formed using poly-Si films after HPWVA, indicating the need for defect termination. The actual solar cell operation demonstrated indicates feasibility of using poly-Si films formed through FLA on glass substrates as a thin-film solar cell material. 相似文献
3.
Ohdaira K Ishii S Tomura N Matsumura H 《Journal of nanoscience and nanotechnology》2012,12(1):591-595
Flash lamp annealing (FLA) with millisecond-order pulse duration can crystallize microm-order-thick a-Si films on glass substrates through explosive crystallization (EC), and flash-lamp-crystallized (FLC) poly-Si films consist of densely-packed nanometer-sized fine grains. We investigate the impact of the hydrogen concentration and the defect density of precursor a-Si films on crystallization mechanism and the microstructures of FLC poly-Si films, by comparing chemical-vapor-deposited (CVD) and sputtered precursor a-Si films. Transmission electron microscopy (TEM) observation reveals that FLC poly-Si films with similar periodic microstructures are formed by the FLA of the two kinds of precursor films, meaning no significant influence of hydrogen atoms and defect density on crystallization mechanism. This high flexibility of the properties of precursor a-Si films would contribute to a wide process window to reproducibly form FLC poly-Si films with the particular periodic microstructures. 相似文献
4.
多晶硅薄膜的铝诱导晶化法制备及其晶粒的择优取向特性 总被引:1,自引:0,他引:1
采用铝诱导非晶硅薄膜晶化技术制备了多晶硅薄膜,并研究了多晶硅的成核和生长特性。非晶硅薄膜采用等离子体增强化学气相沉积法制备,其表面沉积铝薄膜后经不同温度的氮氛围退火处理。结果表明,退火后的硅薄膜层与铝层发生置换,所生长的多晶硅颗粒的平均尺寸约为150nm。X射线衍射分析结果揭示,薄膜的晶向显著依赖于退火温度,较低温度下,铝诱导晶化速率较慢,薄膜的优化晶向与非晶硅薄膜中团簇的初始原子排列趋势紧密相关。而较高温度下,铝诱导晶化促使多晶硅(111)择优成核及随后的固相生长。 相似文献
5.
Lei Zhang Honglie Shen Jiayi You Feng Jiang Tianru Wu Zhengxia Tang 《Journal of Materials Science: Materials in Electronics》2012,23(7):1279-1283
Poly-crystalline silicon (poly-Si) films were fabricated by rapid thermal annealing (RTA) of amorphous silicon films which were deposited on quartz by hot wire chemical vapor deposition. An insertion of Cr layer can significantly suppress the peeling of Si films during the RTA process. The effect of RTA parameters on the structural properties of poly-Si films was investigated by Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that the crystallinity of the poly-Si films is increased with the increase of RTA temperature and duration. A sharp peak at about 520?cm?1 is observed in the Raman spectra of poly-Si films annealed at 900 and 1,100?°C for 15?s indicating the excellent crystallinity of the poly-Si films fabricated by RTA. Poly-Si films with high crystalline fraction of 97.3?% were obtained by RTA at 1,100?°C for 20?s. 相似文献
6.
High-speed μc-Si films deposition and large-grain poly-Si films deposition by surface wave discharge
Microcrystalline silicon (μc-Si) and polycrystalline silicon (poly-Si) films are deposited by surface wave (SW) discharge at 2.45 GHz in H2/SiH4 gas. This high density SW plasma at relatively low pressures (4-60 Pa) enables strong dissociation of feedstock gas. The films deposited on substrate are investigated by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The SW discharge in 10% SiH4 at total pressure of ∼ 30 Pa gives μc-Si films on a substrate at 250 °C, at a fairly high deposition rate of 4-20 nm/s, with a crystalline volume fraction of 0.5-0.8 and a grain size of 10-40 nm. Furthermore, poly-Si film with crystalline volume fraction of > 99% is deposited at higher substrate temperature (400 °C) in 2% SiH4 discharge at lower pressure (4 Pa). X-ray diffraction and SEM results revealed that the grain size of poly-Si films is as large as 600 nm, which is almost 6 times larger than previously reported values. 相似文献
7.
Lei Zhang Honglie Shen Xuefan Jiang Bin Qian Zhida Han Haihong Hou 《Journal of Materials Science: Materials in Electronics》2013,24(11):4209-4212
In this work, rapid thermal annealing (RTA) was employed to crystallize the amorphous silicon films deposited by hot-wire chemical vapor deposition. The influence of annealing temperature on structural and electrical properties was studied by Raman spectroscopy, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and temperature-dependent conductivity measurement. The results show that the amorphous silicon films can be successfully crystallized by RTA in a very short time. The crystallinity and electrical properties of the poly-Si films was greatly improved as the RTA temperature increasing. When the temperature higher than 900 °C, the poly-Si films obtained the crystalline fraction above 95 %, and the hydrogen atoms almost disappeared in the poly-Si films. At the temperature of 1,100 °C, polycrystalline silicon films with conductivity of 16.4 S cm?1 is obtained, which is seven orders in magnitude higher than that of the film annealed at 700 °C. 相似文献
8.
Hydrogenated amorphous silicon (a-Si:H) films were prepared by changing substrate temperature of plasma-enhanced chemical vapor deposition to induce different contents of monohydride and polyhydride bonds, which were then crystallized into polysilicon (poly-Si) films by rapid energy transfer annealing. Fourier transform infrared and transmission spectra show that the formation of numerous polyhydride bonds increases the hydrogen content and reduces the refractive index of a-Si:H films. The rise in the concentration of polyhydride bonds in as-deposited a-Si:H films can result in the increase of ultraviolet reflectance, small peak shift, and change in full width at half maximum of Raman scattering and X-ray diffraction peaks of the obtained poly-Si films after annealing. These results demonstrate that high-concentration polyhydride bonds can promote the rapid crystallization of a-Si:H and obtain high-crystallinity poly-Si films. Transmission electron microscopy identifies that the poly-Si films have the typical dendrite-like grain structure. 相似文献
9.
Bing-Rui WuShih-Yung Lo Dong-Sing Wuu Sin-Liang OuHsin-Yuan Mao Jui-Hao WangRay-Hua Horng 《Thin solid films》2012,520(18):5860-5866
Large grain polycrystalline silicon (poly-Si) films on glass substrates have been deposited on an aluminum-induced crystallization (AIC) seed layer using hot-wire chemical vapor deposition (HWCVD). A poly-Si seed layer was first formed by the AIC process and a thicker poly-Si film was subsequently deposited upon the seed layer using HWCVD. The effects of AIC annealing parameters on the structural and electrical properties of the poly-Si seed layers were characterized by Raman scattering spectroscopy, field-emission scanning electron microscopy, and Hall measurements. It was found that the crystallinity of seed layer was enhanced with increasing the annealing duration and temperature. The poly-Si seed layer formed at optimum annealing parameters can reach a grain size of 700 nm, hole concentration of 3.5 × 1018 cm− 3, and Hall mobility of 22 cm2/Vs. After forming the seed layer, poly-Si films with good crystalline quality and high growth rate (> 1 nm/s) can be obtained using HWCVD. These results indicated that the HWCVD-deposited poly-Si film on an AIC seed layer could be a promising candidate for thin-film Si photovoltaic applications. 相似文献
10.
Keisuke Ohdaira Naohito TomuraShohei Ishii Hideki Matsumura 《Thin solid films》2011,519(14):4459-4461
We investigate residual forms of hydrogen (H) atoms such as bonding configuration in poly-crystalline silicon (poly-Si) films formed by the flash-lamp-induced crystallization of catalytic chemical vapor deposited (Cat-CVD) a-Si films. Raman spectroscopy reveals that at least part of H atoms in flash-lamp-crystallized (FLC) poly-Si films form Si-H2 bonds as well as Si-H bonds with Si atoms even using Si-H-rich Cat-CVD a-Si films, which indicates the rearrangement of H atoms during crystallization. The peak desorption temperature during thermal desorption spectroscopy (TDS) is as high as 900 °C, similar to the reported value for bulk poly-Si. 相似文献
11.
Benjamin Büchter Falko Seidel Ronny Fritzsche Iulia Toader Roy Buschbeck Alexander Jakob Steffen Schulze Hans Freitag Heinrich Lang Michael Hietschold Dietrich R. T. Zahn Michael Mehring 《Journal of Materials Science》2014,49(23):7979-7990
Ultrasonic spray coating is reported as a deposition method for thin silicon films using a mixture of silicon nanoparticles and organosilicon compounds. The as-deposited films were treated by flash lamp annealing (FLA) using xenon light in order to obtain polycrystalline silicon. The nanoparticles were characterized by diffuse reflection infrared Fourier transform spectroscopy, transmission electron microscopy, and powder X-ray diffraction prior to deposition and film formation. The effect of FLA on the morphology of silicon films obtained from these silicon nanoparticles is investigated. Thin polycrystalline films up to 4 µm with a silicon content up to 95 % were prepared by combining the use of ultrasonic spray coating and FLA. 相似文献
12.
S. Steffens C. Becker J.-H. Zollondz A. Chowdhury A. Slaoui S. Lindekugel U. Schubert R. Evans B. Rech 《Materials Science and Engineering: B》2013,178(9):670-675
A variety of defect healing methods was analyzed for optimization of polycrystalline silicon (poly-Si) thin-film solar cells on glass. The films were fabricated by solid phase crystallization of amorphous silicon deposited either by plasma enhanced chemical vapor deposition (PECVD) or by electron-beam evaporation (EBE). Three different rapid thermal processing (RTP) set-ups were compared: A conventional rapid thermal annealing oven, a dual wavelength laser annealing system and a movable two sided halogen lamp oven. The two latter processes utilize focused energy input for reducing the thermal load introduced into the glass substrates and thus lead to less deformation and impurity diffusion. Analysis of the structural and electrical properties of the poly-Si thin films was performed by Suns-VOC measurements and Raman spectroscopy. 1 cm2 cells were prepared for a selection of samples and characterized by I–V-measurements. The poly-Si material quality could be extremely enhanced, resulting in increase of the open circuit voltages from about 100 mV (EBE) and 170 mV (PECVD) in the untreated case up to 480 mV after processing. 相似文献
13.
Aluminum-induced crystallization of amorphous silicon films is discussed. Amorphous Si films were deposited by hot wire chemical vapor deposition onto Al coated glass substrates at 430 °C. Complete crystallization of a-Si films was achieved during a-Si deposition by controlling Al and Si layer thicknesses. The grain structure of the poly-Si films formed on glass substrate was evaluated by optical and electron microscopy. Continuous poly-Si films were obtained using Al layers with a thickness of 500 nm or less. The average grain size was found to be 10-15 μm, corresponding to a grain size/thickness ratio greater than 20. 相似文献
14.
The polycrystalline silicon (poly-Si) thin films were prepared by aluminum induced crystallization. Aluminum (Al) and amorphous silicon (a-Si) layers were deposited using DC sputtering and plasma enhanced chemical vapor deposition method, respectively. For the whole process Al properties of bi-layers can be one of the important factors. In this paper we investigated the structural and electrical properties of poly-crystalline Si thin films with a variation of Al thickness through simple annealing process. All samples showed the polycrystalline phase corresponding to (111), (311) and (400) orientation. Process time, defined as the time required to reach 95% of crystalline fraction, was within 60 min and Al(200 nm)/a-Si(400 nm) structure of bi-layer showed the fast response for the poly-Si films. The conditions with a variation of Al thickness were executed in preparing the continuous poly-Si films for solar cell application. 相似文献
15.
利用电子束蒸镀方法及重掺杂p型硅为蒸发源在K8玻璃衬底上沉积非晶硅薄膜,采用镍诱导晶化法在氮气氛围下进行退火处理制备出p型多晶硅薄膜.研究了不同温度热处理条件对p型多晶硅薄膜的光电性能的影响,通过霍尔测量、拉曼光谱、原子力显微镜、紫外-可见光吸收光谱等测试手段对薄膜进行分析.结果表明,随着晶化温度的提高晶化程度先增强后... 相似文献
16.
Microcrystalline silicon (μc-Si) films were deposited at a high rate and low temperature using jet-type inductively coupled plasma chemical vapor deposition (jet-ICPCVD), and the deposition rate, microstructure and electrical properties of the deposited films were investigated. It was demonstrated that a high deposition rate of over 20 nm/s can be achieved while maintaining high crystallinity and low dark conductivity. The deposition rate is well controlled by regulating the generation rate and transport of growth precursors. High crystallinity of the films results principally from hydrogen-induced chemical annealing. Furthermore, the excellent electrical properties benefit from the low oxygen content and/or low deposition temperature. 相似文献
17.
Sneha Gupta 《Thin solid films》2008,516(5):850-852
Aluminum-induced in situ crystallization (AIC) of amorphous silicon films deposited by hot wire chemical vapor deposition (HWCVD) on glass is demonstrated. Aluminum was deposited at temperatures varying from room temperature to 300 °C on HWCVD a-Si:H films. The AIC was observed to take place in situ during the deposition of Al films, when the glass/a-Si:H temperature is kept 300 °C. A 20-nm Al film was effective in inducing crystallization of about 63% in the a-Si:H film. Thus, separate post-deposition annealing step can be avoided. For an Al film thickness comparable to the amorphous silicon film deposited at an optimum deposition rate, crystallization at temperature as low as 200 °C is observed. It was also observed that the growth pattern of c-Si in case of AIC without post-deposition annealing was identical to AIC with annealing step. 相似文献
18.
Thin (1 μm) a-Si:H films have been deposited on glass at high-deposition rate (8 nm/s) and high substrate temperature (400 °C) by the expanding thermal plasma technique (ETP). After a Solid Phase Crystallization treatment at 650 °C for 10 h, many crystal grains are found to extend over the entire thickness (1 μm) of the polycrystalline silicon (poly-Si) films. This result indicates that the scalable, high-deposition rate ETP method can contribute to increase the potential for a widespread diffusion of poly-Si based thin film solar cells on glass. 相似文献
19.
《Thin solid films》2002,402(1-2):296-301
A new annealing process using hydrogen plasma heating was suggested for the fabrication of poly-Si (polycrystalline silicon) films. This fabrication process had the advantages of low processing temperature approximately 450 °C and a short processing time of 1 h. The a-Si (amorphous silicon) films and a-Si/Pd (palladium) bilayers were deposited by r.f. sputtering and subsequently annealed by conventional furnace heating and hydrogen plasma heating. It was found that the Pd layer, introduced to the surface of the glass substrate prior to deposition of the a-Si layer, enhanced the nucleation reaction of c-Si (crystalline silicon) during the annealing, and that hydrogen plasma heating enhanced the grain growth reaction effectively. These resulted in lowered processing temperature and reduced processing time, while the grain size in the poly-Si films annealed by hydrogen plasma heating was much larger than that in the films by conventional furnace heating. The grain size of the poly-Si films annealed by hydrogen plasma heating was approximately 0.3 μm. 相似文献
20.
High quality polycrystalline silicon (poly-Si) thin films without Si islands were prepared by using aluminum-induced crystallization on glass substrates. Al and amorphous silicon films were deposited by vacuum thermal evaporation and radio frequency magnetron sputtering, respectively. The samples were annealed at 500 °C for 7 h and then Al was removed by wet etching. Scanning electron microscopy shows that there are two layers in the thin films. After the upper layer was peeled off, the lower poly-Si thin film was found to be of high crystalline quality. It presented a Raman peak at 521 cm− 1 with full width at a half maximum of 5.23 cm− 1, which is similar to c-Si wafer. 相似文献