准周期a-Si:H/a-SiN_x:H超晶格

本文首次报道成功地实现了非晶态半导体准周期(无平移对称性)超晶格结构.利用辉光放电汽相淀积技术,由两种超薄的a-Si:H层和a-SiN_x:H层按Fibonacci序列程序淀积而构成一维准周期超晶格.其中两种一维周期格子的调制波长比为黄金分割τ=(1+5~(1/2))/2.剖面电子显微像和相应的电子衍射花样揭示出这类新型非晶态半导体超晶格的奇异性质.简单的理论计算给予实验衍射图像以明确的物理解释.     

等离子刻蚀a-Si:H/a-C:H超晶格

本文介绍了 C_yF_(14)+ O_2等离子刻蚀 a=Si:H/a-C:H 超晶格的工艺原理及方法,简便可行.     

a-Si:H/a-SiGe:H/a-SiGe:H叠层结构太阳能电池性能的数值模拟

本文采用AMPS-1D(Analysis of Microelectronic and Photonic Structures)模拟软件在AM1.5G (100 mW/cm2) 的辐射及室温条件下模拟了a-Si:H/a-SiGe:H/a-SiGe:H三叠层太阳能电池的各项性能。本文首先对三个子电池进行模拟,设定构成叠层电池的三个子电池的带隙分别为1.8、1.6和1.4 eV。计算结果表明：缺陷态是影响电池开路电压及填充因子的重要因素。在对三叠层太阳能电池的数值模拟过程中采用两步匹配法进行电流匹配,并对隧穿结进行优化设计。模拟结果表明：叠层电池的开路电压、填充因子和转换效率在优化隧穿结后都得到提高,且S型的J-V曲线消失。同时本文还对叠层太阳能电池的能带图和载流子复合图进行分析,并将本模拟结果与实验数据相比较,可以得出模拟结果与实验数据符合的较好。     

a-Si:H和a-SiN:H薄膜的质子核磁共振研究

<正> 由辉光放电分解硅烷淀积的氢化非晶态薄膜中都包含相当数量的氢,含氢量的多少直接对薄膜的结构、性质及稳定性有很大的影响。利用核磁共振(1H NMR)可以给出有关氢的局部环境和分布的信息。它与通常所用的红外、ESR、核共振等方法所获得的信息是不同的,因此1H NMR在材料结构分析方面是有其特色的。     

a-Si:H/a-C:H超晶格的界面研究

利用透射电子显微镜(TEM)和电子自旋共振(ESR)分别对a-Si∶H/a-C∶H超晶格的界面结构和自旋电子态进行了研究,发现a-Si∶H/a-C∶H界面存在6-15A的过渡层,而且在界面上还存在面密度约10~(12)cm~(2)的未配对电子,这些未配对电子被证实是非晶硅和非晶碳在界面失配产生的.     

a-Si:H/a-SiN_X:H超晶格的瞬态光致发光

本文用超快速时间分辨光致发光方法研究了a-Si:H/a-SiN_x:H超晶格光生载流子热释和复合的动力学,揭示了超晶格发光衰减时间和带尾宽度随氮含量的非单调变化规     

a-Si:H/a-SiN_x:H多层膜界面的研究

<正> 尽管过去几年对非晶半导体多层膜及其界面对多层膜传输性能影响的研究甚多,然而对于界面缺陷态的特性及其密度了解甚少。不同的测量方法得到的a-Si:H/a-SiNx:H界面缺陷态密度可从1010变到1012cm-2。这一实验结果反映了每一测试方法仅能探测某些能级的缺陷,在某些情况下可能是不同类的缺陷。非晶硅系材料都包含有氢。已发现,在多层膜的沉积过程中,由于组成多层膜的子层间应力释放的需要以及两子层材料的氢扩散系数不同而     

a-Si:H,a-SiC:H和a-SiN:H合金系统中g值的理论计算(英文)

The g-values of the ESR signals caused by dangling bonds in a-Si:H, a-SiC:H and a-SiN:H alloy systems have been calculated for a cluster by using the CNDO method, and compared with the observed g-values. The detailed formula for the calculation of g-values was derived from the formula of A.J.Stone. It is found that the g-values for dangling bonds on Si atoms are affected by the surrounding C or N atoms in a-SiC:H or a-SiN: H alloy systems and the calculated results are in good accordance with the observed ones. Some usefull discussions have also been made.     

a-SiOx:H/a-SiOy:H多层薄膜微结构的退火行为

采用ＰＥＣＶＤ技术在Ｐ型硅衬底上制备了ａ－ＳｉＯｘ：Ｈ／ａ－ＳｉＯｙ：Ｈ多层薄膜,利用ＡＥＳ和ＴＥＭ技术研究了这种薄膜微结构的退火行为,结果表明：ａ－ＳｉＯｘＬ：Ｈ／ａ－ＳｉＯｙ：Ｈ多层薄膜经退火处理形成ｎｃ－Ｓｉ／ＳｉＯ２多层量子点复合膜,膜层具有清晰完整的结构界面,纳米硅嵌埋颗粒呈多晶结构,颗粒大小随退火温度升高而增大小随退火温度升高而增大,在一定的实验条件下,样品在６５０℃下退火可形成尺寸大     

a-Si:H/a-SiN_x:H超晶格薄膜的制备及其性质

本文报道了a-Si:H/a-SiN_x:H超晶格薄膜的制备方法、结构以及在光学方面的量子尺寸效应.     

在a-Si:H/a-SiN_x:H超晶格中导电机制的研究(英文)

We have studied the conduction mechanism of a series of a-Si:H/a-SiNx:H multi-layers samples which have an identical sublayer thickness and periodic numbers, except the ratio of N/Si in a-SiNx:H sublayers. It is shown that the temperature characteristic of conductivity of these samples has a kink point in the range of 120-140℃. The kink temperature and the acttivation energy of conductivity are related to the N/Si ratio in the a-SiNx:H sublayers. We recognized preliminarily that the mechanism above and below the kink temperature could be the bulk or the interfacial conduction in a-Si:H well layers.     

a—SiNx：H薄膜对a—Si：H TFT阈值电压的影响

介绍了测定a－Si：HTFT闽值电压的实验方法。重点研究了改变a－SiNx：H薄膜淀积时反应气体NH3／SiH4流速比以及a－SiNx:H膜厚对a－Si：HTFT阈值电压的影响。对实验结果进行了分析。实验结果表明：a－Si:HTFT的阈值电压随a－SiNx：H的膜厚增加而增大；增大X－SiNx：H薄膜淀积时NH3／SiH4气体流速比，可明显减小a-Si:HTFT的阈值电压。     

氮含量对a-Si:H/a-SiN_x:H多层膜界面及光学性质的影响(英文)

We have studied TV content influence in two ranges of x(R1.,R2) by Raman, PL, IR spectra on PCVD a-Si:H/a-SiNx:H samples with constant sublayer thickness and cycle number but whole range of x respectively. Raman shows that the FWHM of TO-like peaks increases with x in range R1 and so does the bond angle fluctuation. PL exhibits that the band tail width increases and the NR activation energy as well as the PL efficiency decrease? with x in R1, because of the increase of lattice strain introduced by structural mismatch at interfaces. The above parameters change towards the opposite direction in R2 with a turn at x=0.9, This might be caused by the structure change of a-SiNx into Si3N4 and the greatly increasing of N-H bonds in R2, which enhances the softness of the matrix and relaxes the lattice strain.     

a-Si:H/a-SiN_x:H超晶格氮含量对界面及光电导温度特性的影响(英文)

The paper reports the effects of nitrogen content on the temperature dependence of photoconductivity σρ(T) and interface states NS in a-Si:H/ a-SiNx:H super-lattices by means of electroabsorption (EA) photothermal deflection spectroscopy (PDS). A critical value of nitrogen content for Ns and for intensity of N-H bond was found to be 0.6. The computer fitting of σρ(T) to determine the interface states was carried out which vas consistent with the results by PDS. A model of charged nitrongen dangling bond to illustrate the above results is discussed here.     

Investigation of Induced Distortions in a-Si∶H/a-SiNx∶H Multilayers by Raman Scattering Technique

The a-Si∶H/SiNx∶H sample series are investigated by means of Raman scattering technique(RST). The result shows that due to the structural mismatch between a-Si∶H and a-SiNx∶H, severe induced distortions are produced in the interface of the heterojunction, and these induced distortions tend towards a certain energy state. The ordering of the interface structure depends on the periodic number of multilayer thin films.     

Fully self-aligned tri-layer a-Si:H thin-film transistors withdeposited doped contact layer

We demonstrate a new self-aligned TFT process for hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs). Two backside exposure photolithography steps are used to fabricate fully self-aligned tri-layer TFTs with deposited n⁺ contacts. Since no critical data alignment is required, this simple process is well suited to fabrication of short channel TFTs. We have fabricated fully self-aligned tri-layer a-Si:H TFTs with excellent device performance, and contact overlaps <1 μm. For a 20-μm channel length TFT with an a-Si:H thickness of 13 nm, the linear region (V_DS=0.1 V) and saturation region (V_DS=25 V) extrinsic mobility values are both 1.2 cm²/V-s, the off currents are <1 pA, and the on/off current ratio is >10⁷     

脉冲激光辐照下半导体薄膜中温度场的计算

利用理论模型求得了脉冲激光辐照半导体薄膜材料的温度场解析解。结合ＫｒＦ准分子脉冲激光对淀积在熔凝石英衬底上的ａ－ＳｉＨ薄膜以及ａ－ＳｉＨ／ａ－ＳｉＮｘＨ多量子阱结构材料的热退火处理，分析了膜厚、激光能量密度以及ａ－ＳｉＨ／ａ－ＳｉＮｘＨ多量子阱结构材料中的子层厚度比对温度场性质及ａ－ＳｉＨ薄膜的晶化效果的影响。     

低温高速率沉积非晶硅薄膜及太阳电池

采用射频等离子体增强化学气相沉积(RF-PECVD)技术,保持沉积温度在125℃制备非晶硅薄膜材料及太阳电池。在85 Pa的低压下以及400～667 Pa的高压下,改变Si H4浓度和辉光功率等沉积参数,对本征a-Si材料的性能进行优化。结果表明,在高压下,合适的Si H4浓度和压力功率比可以使a-Si材料的光电特性得到优化,并且薄膜的沉积速率得到一定程度的提高。采用低压低速和高压高速的沉积条件,在125℃的低温条件下制备出效率为6.7%的单结a-Si电池,高压下本征层a-Si材料的沉积速率由0.06～0.08 nm/s提高到0.17～0.19 nm/s。     

制备可见光致发光硅量子阱的激光晶化技术

我们利用Ａｒ＋激光辐照ａ－Ｓｉ：Ｈ／ａ－ＳｉＮｘ：Ｈ多量子阱结构材料，使ａ－Ｓｉ：Ｈ阱层晶化。在该样品中成功地观察到室温可见光致发光现象，研究了阱层厚度和激光辐照功率对光致发光峰峰位及半高宽的影响。