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1.
本文采用甚高频等离子体增强化学气相沉积技术制备了沉积速率系列不同生长阶段的微晶硅薄膜,通过椭圆偏振技术研究了生长过程中微晶硅薄膜表面粗糙度的演化.实验结果表明:沉积速率为0.08和0.24nm/s的低速沉积时,硅薄膜表面粗糙度接近,生长指数分别为β=0.21和β=0.20,对应有限扩散生长模式,此时沉积速率对硅薄膜生长影响不大,原因是低速沉积时成膜先驱物有足够时间迁移到能量低的位置;当沉积速率增加到0.66nm/s时,硅薄膜表面粗糙度明显增加,生长指数β=0.81,大于0.5,出现了异常标度行为,与低速沉积的生长模式明显不同,原因是高速沉积时成膜前驱物来不及扩散就被下一层前驱物覆盖,降低了成膜前驱物在薄膜表面的扩散,使表面粗糙度增加和生长指数β增大.β大于0.5的异常标度行为与阴影效应有关. 相似文献
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采用甚高频等离子体增强化学气相沉积技术高速沉积了有无籽晶层两个系列微晶硅薄膜,通过椭圆偏振光谱、拉曼光谱和XRD对薄膜进行了分析,发现采用籽晶层后,在薄膜沉积初期有促进晶化的作用;由于籽晶层减少了薄膜的诱导成核时间,提高了薄膜的沉积速率,对比了实时在线和离线椭圆偏振光谱两种测量状态对分析微晶硅薄膜的影响,研究发现,当薄膜较薄时,实时在线测量得到的薄膜厚度小于离线下的数值;当薄膜较厚时,两种测量条件下得到的薄膜厚度差异较小;实时在线条件下得到的表面粗糙度要大于离线条件下得到的数值,这是由于薄膜暴露在大气中后表面有硅氧化物生成,对表面有平滑作用. 相似文献
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采用等离子体增强化学气相沉积技术沉积一系列处于不同生长阶段的微晶硅薄膜.通过同步辐射X射线掠角反射技术研究微晶硅薄膜的表面粗糙度随时间等的演化,探讨微晶硅薄膜的生长动力学过程及其生长机制.研究结果表明,在衬底温度为200 ℃,电极间距为2 cm,沉积气压为6.66×102 Pa,射频功率密度为0.22 W/cm2,氢稀释度分别为99%和98%的沉积条件下,在玻璃衬底上生长的微晶硅薄膜生长指数β分别为0.21±0.01和0.24±0.01.根据KPZ模型,微晶硅薄膜的生长机制为有限扩散生长.
关键词:
X射线掠角反射
微晶硅薄膜
表面粗糙度
生长机制 相似文献
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The effect of initial discharge conditions on the properties of microcrystalline silicon thin films and solar cells 下载免费PDF全文
This paper studies the effects of silane back diffusion in
the initial plasma ignition stage on the properties of
microcrystalline silicon ($\mu $c-Si:H) films by Raman spectroscopy
and spectroscopic ellipsometry, through delaying the injection of
SiH7280N, 7830G, 8115H http://cpb.iphy.ac.cn/CN/10.1088/1674-1056/19/5/057205 https://cpb.iphy.ac.cn/CN/article/downloadArticleFile.do?attachType=PDF&id=111771 back diffusion, microcrystalline silicon, thin film, Raman
crystallinity Project supported by the State Key
Development Program for Basic Research of China (Grant
No.~2006CB202601). This paper studies the effects of silane back diffusion in
the initial plasma ignition stage on the properties of
microcrystalline silicon ($\mu $c-Si:H) films by Raman spectroscopy
and spectroscopic ellipsometry, through delaying the injection of
SiH$_{4}$ gas to the reactor before plasma ignition. By comparing
with standard discharge condition, delayed SiH$_{4}$ gas condition
could prevent the back diffusion of SiH$_{4}$ from the reactor to
the deposition region effectively, which induced the formation of a
thick amorphous incubation layer in the interface between bulk film
and glass substrate. Applying this method, it obtains the
improvement of spectral response in the middle and long wavelength
region by combining this method with solar cell fabrication.
Finally, results are explained by modifying zero-order analytical
model, and a good agreement is found between model and experiments
concerning the optimum delayed injection time. back;diffusion;microcrystalline;silicon;thin;film;Raman;crystallinity This paper studies the effects of silane back diffusion in the initial plasma ignition stage on the properties of microcrystalline silicon(μc-Si:H) films by Raman spectroscopy and spectroscopic ellipsometry,through delaying the injection of SiH4 gas to the reactor before plasma ignition.Compared with standard discharge condition,delayed SiH4 gas condition could prevent the back diffusion of SiH4 from the reactor to the deposition region effectively,which induced the formation of a thick amorphous incubation layer in the interface between bulk film and glass substrate.Applying this method,it obtains the improvement of spectral response in the middle and long wavelength region by combining this method with solar cell fabrication.Finally,results are explained by modifying zero-order analytical model,and a good agreement is found between the model and experiments concerning the optimum delayed injection time. 相似文献
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本文采用射频等离子体增强化学气相沉积(rf-PECVD)技术在单晶硅衬底上沉积了两个系列的硅薄膜. 通过对样品进行固定角度椭圆偏振测试, 结果表明第一个系列硅薄膜为非晶硅, 形成了突变的a-Si:H/c-Si异质结构, 此结构在HIT电池中有利于形成好的界面特性, 对于非晶硅薄膜采用通常的Tauc-Lorentz摇摆模型(Genosc)拟合结果很好; 第二个系列硅薄膜为外延硅, 对于外延硅薄膜, 随着膜厚增加晶化率降低, 当外延硅薄膜厚度为46 nm时开始非晶硅生长. 对于外延硅通常采用EMA模型(即将硅薄膜体层看成由非晶硅和c-Si构成的混合层)拟合结果较好, 当硅薄膜中出现非晶硅生长时, 将体层分成混合层和非晶硅两层, 采用三层模型拟合结果很好. 本文证实了椭偏光谱分析采用不同的模型可对单晶硅衬底上不同结构的硅薄膜进行有效表征. 相似文献
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The study of amorphous incubation layers during the growth of microcrystalline silicon films under different deposition conditions 下载免费PDF全文
<正>The structural un-uniformity of μc-Si:H films prepared using a very high frequency plasma-enhanced chemical vapour deposition method has been investigated by Raman spectroscopy,spectroscopic ellipsometer and atomic force microscopy.It was found that the formation of amorphous incubation layer was caused by the back diffusion of SiH_4 and the amorphous induction of glass surface during the initial ignition process,and growth of the incubation layer can be suppressed and uniformμc-Si:H phase is generated by the application of delayed initial SiH_4 density and silane profiling methods. 相似文献
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Microcrystalline silicon (μc-Si:H) thin films with and without boron doping are deposited using the radio-frequency plasma-enhanced chemical vapour deposition method. The surface roughness evolutions of the silicon thin films are investigated using ex situ spectroscopic ellipsometry and an atomic force microscope. It is shown that the growth exponent β and the roughness exponent α are about 0.369 and 0.95 for the undoped thin film, respectively. Whereas, for the boron-doped μc-Si:H thin film, β increases to 0.534 and α decreases to 0.46 due to the shadowing effect. 相似文献
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采用VHF-PECVD技术制备了系列不同硅烷浓度和反应气压的微晶硅薄膜.运用拉曼散射光谱和 x射线衍射对制备的材料进行了结构分析.在实验研究的范围内,制备材料的晶化程度随硅烷 浓度的增加而降低.XRD的测试结果表明:制备的微晶硅材料均体现了(220)方向择优.应用在 电池的有源层中,制备出了效率达7.1%的单结微晶硅太阳电池,电池的结构是glass/ZnO/p( μc-Si:H)/i(μc-Si:H)/n(a-Si:H/Al),没有ZnO背反射电极,有源层的厚度仅为1.2μm.
关键词:
本征微晶硅薄膜
拉曼光谱
x射线衍射 相似文献
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采用x射线小角散射(SAXS)技术研究了由射频等离子体增强化学气相沉积(rf-PECVD)、 热丝化学气相沉积(HWCVD)和等离子体助热丝化学气相沉积(PE-HWCVD)技术制备的微晶硅( μc-Si:H)薄膜的微结构.实验发现,在相同晶态比的情况下,PECVD沉积的μc-Si:H薄膜微 空洞体积比小,结构较致密,HWCVD沉积的μ-Si:H薄膜微空洞体积比大,结构较为疏松,PE -HWCVD沉积的μc-Si:H薄膜,由于等离子体的敲打作用,与HWCVD样品相比,微结构得到明 显改善.采用HWCVD二步法和PE-HWCVD加适量Ar离子分别沉积μc-Si:H薄膜,实验表明,微结 构参数得到了进一步改善.45°倾角的SAXS测量显示,不同方法制备的μc-Si:H薄膜中微空 洞分布都呈各向异性.红外光谱测量也证实了SAXS的结果.
关键词:
微晶硅薄膜
微结构
微空洞
x射线小角散射 相似文献
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报道了SiCl4/H2等离子体化学气相沉积方法制备的未掺杂微晶硅薄 膜,在短时间光照或加上直流偏压后其室温暗电导随时间缓慢变化的行为. Raman散射谱结 果表明,薄膜的晶态体积比大于70%. 暗电阻的实验结果显示: 材料具有弱的持久光电导效 应;薄膜的暗电导在外加直流电场的作用下缓慢上升,电场反向后出现暗电导的恢复过程, 而且暗电导变化速度与偏压大小和温度有关. 根据异质结势垒模型,指出外加条件下载流子 的空间分离和重新分布以及材料非均匀性造成的势垒是引起电导
关键词:
微晶硅
电导率
薄膜 相似文献
14.
Effect of substrate temperature and pressure on properties of microcrystalline silicon films 下载免费PDF全文
In this paper intrinsic microcrystalline silicon films have been prepared by very high
frequency plasma enhanced chemical vapour deposition (VHF-PECVD) with
different substrate temperature and pressure. The film properties were
investigated by using Raman spectra, x-ray diffraction, scanning
electron microscope (SEM), and optical
transmittance measurements, as well as dark conductivity. Raman results
indicate that increase of substrate temperature improves the microcrystallinity
of the film. The crystallinity is improved when the pressure increases from
50Pa to 80Pa and the structure transits from microcrystalline to amorphous
silicon for pressure higher than 80Pa. SEM reveals the effect of substrate
temperature and pressure on surface morphology. 相似文献
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为提高微晶硅薄膜的纵向结晶性能, 在甚高频等离子体增强化学气相沉积技术的基础上, 采用过渡参数缓变和两步法相结合的方法在普通玻璃衬底上高速沉积薄膜. 当功率密度为2.1 W/cm2, 硅烷浓度在6%和9.6%之间变化时, 从薄膜方向和玻璃方向测算的Raman晶化率的差异维持在2%以内. 硅烷浓度为9.6%时, 薄膜沉积速率可达3.43 nm/s, 从薄膜方向和玻璃方向测算的Raman晶化率分别为50%和48%, 差异的相对值仅为4.0%. 合理控制过渡阶段的参数变化, 可使两个方向的Raman晶化率差值下降到一个百分点. 表明采用新方法制备薄膜, 不仅可以抑制非晶孵化层的形成, 改善微晶硅薄膜的纵向结构, 还为制备优质薄膜提供了较宽的参数变化空间.
关键词:
微晶硅薄膜
非晶孵化层
高速沉积
甚高频等离子体增强化学气相沉积 相似文献
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采用甚高频等离子体增强化学气相沉积(VHF-PECVD)技术制备了不同腔室环境下的微晶硅薄膜.对单室沉积掺杂层p材料后遗留在腔室中的硼对本征微晶i材料电学特性和结构特性的影响进行了详细研究.测试结果表明:单室沉积p层后的硼降低了微晶i层材料的暗电导,增加了材料的光敏性;由于硼对i层污染程度的不同,使得材料的激活能发生了变化;腔室中残余的硼也导致微晶硅薄膜的结晶状况恶化,同时弱化了材料的(220)择优取向.而在较高功率和较强氢稀释下制备的晶化率较高,(220)晶向明显择优的材料受硼污染影响相对减小.
关键词:
单室
甚高频等离子体增强化学气相沉积
微晶硅
硼 相似文献
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Effects of deposition pressure and plasma power on the growth and properties of boron-doped microcrystalline silicon films 下载免费PDF全文
Using diborane as doping gas, p-doped μc-Si:H layers are deposited by using the plasma enhanced chemical vapour deposition (PECVD) technology. The effects of deposition pressure and plasma power on the growth and the properties of μc-Si:H layers are investigated. The results show that the deposition rate, the electrical and the structural properties are all strongly dependent on deposition pressure and plasma power. Boron-doped μc-Si:H films with a dark conductivity as high as 1.42 Ω^-1·cm^-1 and a crystallinity of above 50% are obtained. With this p-layer, μc-Si:H solar cells are fabricated. In addition, the mechanism for the effects of deposition pressure and plasma power on the growth and the properties of boron-doped μc-Si:H layers is discussed. 相似文献
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以B2H6为掺杂剂,采用射频等离子体增强化学气相沉积技术在玻璃衬底上制备p型氢化微晶硅薄膜.研究了衬底温度和硼烷掺杂比对薄膜的微结构和暗电导率的影响.结果表明:在较高的衬底温度下很低的硼烷掺杂比即可导致薄膜非晶化;在实验范围内,随着衬底温度升高薄膜的晶化率单调下降,暗电导率先缓慢增加然后迅速下降,变化趋势与硼烷掺杂比的影响极为相似.最后着重讨论了p型氢化微晶硅薄膜的生长机理.
关键词:
p型氢化微晶硅薄膜
衬底温度
晶化率
电导率 相似文献
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Hydrogenated silicon (Si:H) thin films for application in solar cells were deposited
by using very high frequency plasma enhanced chemical vapour deposition (VHF PECVD)
at a substrate temperature of about 170℃. The electrical, structural, and
optical properties of the films were investigated. The deposited films were then
applied as i-layers for p-i-n single junction solar cells. The current--voltage
(I-V) characteristics of the cells were measured before and after the light
soaking. The results suggest that the films deposited near the transition region
have an optimum properties for application in solar cells. The cell with an i-layer
prepared near the transition region shows the best stable performance. 相似文献