氧化铝膜对铝诱导制备多晶硅薄膜的影响

为了考察硅铝界面氧化铝膜对铝诱导多晶硅的影响,本文用磁控溅射方法制备了界面有无氧化铝膜的硅铝复合结构。XRD测试表明两种铝诱导方法均制备了具有(111)高度择优取向的多晶硅薄膜。光学显微镜和扫描电镜照片显示,有氧化铝膜时铝诱导的多晶硅薄膜有两层,下层为大晶粒(40μm-60μm)枝晶状多晶硅,拉曼谱显示其结晶质量接近单晶,而上层膜晶粒较小,结晶质量较差。无氧化铝膜时铝诱导的多晶硅薄膜只有单层结构,其晶体结构和结晶质量都与有氧化铝膜时铝诱导的上层多晶硅薄膜相似。结果表明,硅铝界面上氧化铝的存在大大提高了铝诱导多晶硅薄膜的质量,但是另一方面也限制了铝诱导多晶硅的晶化速率。     

铝诱导晶化P型非晶硅薄膜实验研究

利用PECVD设备在普通玻璃基片上沉积硼掺杂P型非晶硅薄膜,采用铝诱导晶化法（AIC）在氮气气氛保护下进行退火处理制备出P型多晶硅薄膜,研究了不同厚度的金属铝膜和热处理温度对非晶硅薄膜的微观结构、表面形貌的影响。实验结果表明：铝膜相对厚度越厚,对a—Si的晶化诱导效果则越好,在一定温度条件下,相对较厚的铝膜可以缩短a—Si晶化为polv-Si的时间,并且能使a—Si的晶化更加完整,产生尺寸较大的硅晶颗粒。在铝膜厚度相同,退火温度相同的条件下,热处理的时间越长,则晶化发生的程度越深,晶化越为彻底。     

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

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。     

非均匀的纳米晶硅(nc-Si)薄膜的横向热伏效应

采用磁控溅射技术在石英衬底上沉积1层200nm厚的非晶硅(a-Si)薄膜,并用真空热蒸发在其上沉积两个横向接触的厚度不同(分别为50和100nm)的Al膜.将已沉积好的薄膜在N2气氛中600℃下退火45min,得到两个横向接触的具有不同晶化程度的纳米晶硅(nc-si)薄膜.利用X射线衍射(XRD)、Raman光谱、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了所制备样品的结构特性.由较厚Al膜诱导的nc-Si薄膜的Si晶粒平均尺寸为25nm,晶化率为56%;由较薄Al膜诱导的nc-Si薄膜的Si晶粒平均尺寸为15nm,晶化率为23%.实验发现在没有温度梯度的情况下,这两个不同晶化程度的nc-Si薄膜之间具有横向热伏效应.温度为273K时,其开路电压为1.2mV,短路电流为40nA;当温度达到373K时,其开路电压达到25mV,短路电流达到1.171μA.     

电子束蒸发与磁控溅射制备Al/PI复合薄膜的性能研究

利用磁控溅射法和电子束蒸发法在聚酰亚胺(PI)薄膜基底上沉积了铝功能膜.测试了两种方法薄膜的膜厚、附着力、反射率、折射率和电导率.结果表明,磁控溅射法制备的铝膜的综合性能较电子束蒸制备的铝膜的性能优越.     

铝诱导晶化法低温制备多晶硅薄膜

为了满足在普通玻璃衬底上制备多晶硅薄膜晶体管有源矩阵液晶显示器,低温（＜６００℃）制备高质量多晶硅薄膜已成为研究热点．本文研究了一种低温制备多晶硅薄膜的新工艺：金属诱导非晶硅薄膜低温晶化法．在非晶硅薄膜上蒸镀金属铝薄膜,并光刻形成铝膜图形,而后于氮气保护中退火．利用光学显微镜和拉曼光谱等测试方法,研究了Ａｌ诱导下非晶硅薄膜的晶化过程,结果表明;在５６０℃退火６ｈ后;铝膜下的非晶硅已完全晶化,确定了所制备的是多晶硅薄膜．初步探讨了非晶硅薄膜金属诱导横向晶化机理．     

铝诱导晶化制备多晶硅薄膜研究进展

铝诱导晶化(AIC)技术制备多晶硅(Poly-Si)薄膜因处理温度低、退火时间短,且所制备的薄膜晶粒尺寸大而受到广泛关注。阐述了AIC法制备Poly-Si薄膜的交换机制,着重讨论了AIC过程中工艺条件对制备Poly-Si薄膜质量的影响,简单介绍了AIC制备的Poly-Si薄膜在太阳电池器件方面的研究现状,并指出提高AIC法制备的Po-ly-Si薄膜籽晶层及外延层质量以改善薄膜电池性能是今后的重点研究方向。     

退火对铝诱导结晶锗薄膜的影响及其机理

为实现在Si衬底上制备GaInP/GaInAs/Ge三结太阳电池,本工作尝试利用磁控溅射和常规退火技术,采用铝诱导结晶(AIC)法在(100)晶面单晶硅衬底上制备Ge薄膜,利用金相显微镜(Metallographic microscopy)、X射线衍射仪(XRD)、拉曼光谱仪(Raman)对其进行表征。分析了铝诱导过程中退火时间和退火温度对Ge薄膜结晶性的影响,发现退火温度越低、时间越长,制备的薄膜质量越好,确定了Ge薄膜晶化的最低退火温度为250℃,并在该温度下成功制备出了晶粒尺寸超过100nm、Ge(111)晶面择优取向度达到99%以上的Ge薄膜。     

PVDF薄膜的低维化制备和结构研究

采用真空热蒸发技术在单晶硅基底上沉积PVDF薄膜.通过分析阻蒸温度对薄膜沉积速率和真空室气压变化的影响研究了PVDF镀膜过程.同时利用傅立叶变换衰减全反射红外光谱(ATR-FTIR)、X射线衍射(XRD)和差热分析(DSC)对薄膜的晶型结构进行了表征分析,结果发现,真空热蒸发技术可制备具有高度取向性的α晶相PVDF薄膜,且薄膜中不舍C=C键.相比于PVDF树脂粉末,所得薄膜的结晶度明显增大而分子量显著减小,实现了PVDF薄膜的低维化制备.     

金属镍诱导p型多晶硅薄膜的光电性能研究

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...     

Influence of rapid thermal annealing on the process of aluminum induced crystallization of amorphous Si

The effects of annealing methods on the crystallization process and microstructure of polycrystalline silicon (poly-Si) films obtained by aluminum-induced crystallization (AIC) of amorphous Si (a-Si) films were comparatively investigated. Glass/Al/a-Si structures were annealed by rapid thermal annealing (RTA) and conventional furnace at 500 °C for different times in Ar. As compared to furnace annealing, AIC of a-Si films annealed by RTA possesses a shorter period of nucleation time, a higher nucleation density and reduces the process time to form continuous poly-Si films. It is revealed that the continuous Si films obtained by both RTA and conventional furnace annealing are polycrystalline in nature, exhibiting good microstructures with Raman peaks at 518 cm^?1 and full-width at half-maximums of 6.43–6.48 cm^?1.     

A low‐cost and reliable optical inspection system for rapid surface roughness measurements of polycrystalline thin films

Excimer laser crystallization is a well‐known industrially used technique to produce high‐performance polycrystalline silicon thin films on the commercially available inexpensive glass substrates for the development of high‐performance low temperature polycrystalline silicon thin‐film transistors in active matrix flat panel displays. A rapid optical measurement system for rapid surface roughness measurement of polycrystalline silicon thin films was developed in this study. Two kinds of thicknesses of polycrystalline silicon thin films were used to study rapid surface roughness measurements. Six different incident angles were employed for measuring surface roughness of polycrystalline silicon thin films. The results reveal that the incident angle of 20° was found to be a good candidate for measuring surface roughness of polycrystalline silicon thin films. Surface roughness (y) of polycrystalline silicon thin films can be determined rapidly from the average value of reflected direct current voltage (x) measured by the optical system developed using the trend equation of y = –8.9854x + 91.496. The maximum measurement error rate of the optical measurement system developed was less than 5.72%. The savings in measurement time was up to 83%.     

Direct growth of large grain polycrystalline silicon films on aluminum-induced crystallization seed layer using hot-wire chemical vapor deposition

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.     

Effect on thickness of Al layer in poly-crystalline Si thin films using aluminum(Al) induced crystallization method

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.     

Epitaxial and polycrystalline BaFe12O19 thin films grown by chemical vapour deposition

Epitaxial and polycrystalline barium hexaferrite BaFe₁₂O₁₉ thin films were prepared by metalorganic chemical vapour deposition (MOCVD). Films were grown by a liquid MOCVD technique which aim is to control precisely the precursor vapour pressures. Two kinds of substrates were used: sapphire (001) and silicon thermally oxidized. On Si/SiO₂ films are polycrystalline and the magnetization is isotropic. On Al₂O₃ (001), structural studies reveal the films to be predominantly single phase, well crystallized without annealing procedure and with the c-axis perpendicular to the film plane; epitaxial relationships between the film and the substrate were determined. The magnetic parameters, deduced from vibrating sample magnetometer measurements, show a high dependence of the magnetization with the orientation of the field with respect to the surface of the film.     

Aluminum-induced in situ crystallization of HWCVD a-Si:H films

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.     

fabrication of diamond membranes for MEMS using reactive ion etching of silicon

Polycrystalline diamond thin film has been grown on a silicon substrate using high pressure microwave plasma-assisted chemical vapor deposition from a gas mixture of methane and hydrogen at a substrate temperature of 950°C. A simple process flow has been developed to fabricate optically transparent polycrystalline synthetic diamond membranes/windows employing reactive ion etching (RIE) of a single crystal silicon substrate using an electron beam evaporated aluminum thin film mask pattern formed by photolithography. Scanning electron microscopy has been used to study the morphology of as-grown diamond thin films.