Elastically Strained Porous Silicon Layers Formed on Single-Crystal Substrates

Elastically strained porous silicon layers on single-crystal substrates are fabricated and examined. It is established that (i) the strain-related properties of the layers can be varied by adjusting the process conditions and (ii) the layers could be useful for the low-temperature gettering of impurities and defects from silicon single crystals.     

脉冲腐蚀法制备多孔硅及其光学特性研究

Labview软件控制腐蚀条件,用脉冲电化学腐蚀法制备多孔硅薄膜,其表面形貌用原子力显微镜观察并分析。用可见-紫外分光光度仪测量其反射谱,通过计算得出各种制备条件下,多孔硅薄膜的其它光学参数,即有效折射率neff,吸收系数α,有效介电常数的实部εer,和虚部εei,消光系数K,研究了入射光波长和孔隙率对这些光学常数的影响。     

脉冲腐蚀法制备多孔硅及其光学特性研究

Labview软件控制腐蚀条件,用脉冲电化学腐蚀法制备多孔硅薄膜,其表面形貌用原子力显微镜观察并分析。用可见-紫外分光光度仪测量其反射谱,通过计算得出各种制备条件下,多孔硅薄膜的其它光学参数,即有效折射率neff,吸收系数α,有效介电常数的实部εer和虚部εei,消光系数K。研究了入射光波长和孔隙率对这些光学常数的影响。     

双槽电化学腐蚀法制备多孔硅的研究

论述了多孔硅的特点和制备方法,简单介绍双槽电化学腐蚀法的特点,并采用双槽电化学腐蚀法成功制备了多孔硅。多孔硅的扫描电镜(SEM)照片表明,孔径尺寸小,均匀性好,腐蚀结构规则。实验结果表明,衬底导电类型影响着多孔硅的制备条件。     

Formation of Luminescent Silicon Nanowires and Porous Silicon by Metal-Assisted Electroless Etching

Metal-assisted etching of silicon in HF/H₂O₂ aqueous solutions has been used to fabricate luminescent silicon nanowires (SiNWs) and porous silicon. The impact of the gold catalyst layer thickness and the etching solution on the morphology of the synthesized nanostructures and the diameter of the obtained nanowires were systematically investigated. Scanning electron microscopy (SEM) analyses reveal that the morphology of the fabricated structures strongly depends on the composition of the solution and the thickness of the catalyst layer. It has been observed that SiNWs are formed in solutions with H₂O₂ ratios (ξ) below 10 %; increasing the H₂O₂ concentration above this critical value leads to mesoporous (10 % < ξ < 14 %) and macroporous (14 % < ξ < 17 %) structures. Photoluminescence measurements show that SiNWs emit light at about 430 nm. Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) analyses were utilized to determine the origin of the emission in the silicon nanostructures. TEM imaging demonstrates that SiNWs are covered by a thin layer of porous silicon, which is assumed to be responsible for their light emission.     

Optical and Structural Properties of Ag and c-Si Nanostructures Formed During the Metal-Assisted Chemical Etching of Silicon

Semiconductors - This study consisting of two parts is concerned with the features of the three-stage process of the metal-assisted chemical etching (MACE) of silicon. This process is used to...     

多孔硅的化学浸蚀制备与表征

以不同电阻率的p型单晶硅片为研究对象,通过正交实验对化学浸蚀法制备多孔硅的工艺条件进行优化,采用多种仪器对制备的多孔硅比表面积、膜厚、表面形貌、化学组成及光致发光进行表征.结果表明,p型单晶硅片经化学浸蚀后能够形成多孔硅,其膜厚达到3 μm;延长浸蚀时间,多孔硅比表面积和膜厚呈先增大后减小的趋势,但化学浸蚀时间太长将导致局部区域的多孔硅层坍塌;室温条件下,多孔硅可光致发光,由于孔洞尺寸分布范围较窄,多孔硅发光半峰宽较窄.     

多孔硅衬底上ZnS薄膜的PLD制备和表征

在电化学阳极氧化法制备的多孔硅（porous silicon,PS）衬底上用脉冲激光沉积法（pulsed laser deposition,PLD）在250℃和350℃下生长ZnS薄膜。XRD图样显示,制备的ZnS薄膜沿β—ZnS（111）方向择优生长,较高的生长温度下,衍射峰强度较大。SEM结果表明,250℃生长的Z...     

电化学脉冲腐蚀法制备窄峰发射的多孔硅微腔

用电化学脉冲腐蚀方法制备了多孔硅微腔 ,讨论了脉冲电化学腐蚀的参数——周期、占空比对多孔硅多层膜制备的影响 ,并用了以 HF酸扩散为基础的多孔硅动态腐蚀机理对实验结果进行解释 ,认为在用电化学脉冲腐蚀法制备多孔硅微腔的过程中 ,不但要考虑到 HF酸对硅的纵向电流腐蚀 ,也要考虑到 HF酸对多孔硅硅柱的横向浸泡腐蚀 .可通过选取合适的周期、占空比 ,使二者对多孔硅的作用达到适中 ,以制备出高质量的多孔硅多层膜和微腔 .并用正交实验法优化了制备多孔硅微腔的参数 ,根据优化的实验参数 ,制备出了发光峰半峰宽为 6 nm的多孔硅微腔     

电化学脉冲腐蚀法制备窄峰发射的多孔硅微腔

用电化学脉冲腐蚀方法制备了多孔硅微腔,讨论了脉冲电化学腐蚀的参数--周期、占空比对多孔硅多层膜制备的影响,并用了以HF酸扩散为基础的多孔硅动态腐蚀机理对实验结果进行解释,认为在用电化学脉冲腐蚀法制备多孔硅微腔的过程中,不但要考虑到HF酸对硅的纵向电流腐蚀,也要考虑到HF酸对多孔硅硅柱的横向浸泡腐蚀.可通过选取合适的周期、占空比,使二者对多孔硅的作用达到适中,以制备出高质量的多孔硅多层膜和微腔.并用正交实验法优化了制备多孔硅微腔的参数,根据优化的实验参数,制备出了发光峰半峰宽为6nm的多孔硅微腔.     

Structural and Spectroscopic Studies of Epitaxial GaAs Layers Grown on Compliant Substrates Based on a Superstructure Layer and Protoporous Silicon

Semiconductors - The purpose of the study is to investigate the effect of a new type of compliant substrate based on an AlGaAs superstructure layer (SL) and a protoporous Si (proto-Si) layer formed...     

直拉重掺硼硅单晶的碱腐蚀特性研究

直拉重掺硅硼单晶作为重要的外延衬底材料,具有其优越的特性。由于其硬度大,杂质含量高．在抛光片的加工过程中表现出腐蚀速率慢、表面均匀性差等特点,不利于硅片腐蚀减薄和抛光清洗等。研究了直拉重掺硅硼单晶的碱性腐蚀速率随腐蚀液温度和浓度变化趋势,从直拉重掺硅硼单晶化学反应的微观角度解释了这种变化规律,在此基础上,研究了不同的添加剂对腐蚀速率和表面均匀性的影响,从理论和实验两方面证实了,在腐蚀液中加入碱性氧化剂有利于腐蚀速率的提高,并能有效改善硅片的表面均匀性。     

Temperature Effects on Photoluminescence Properties of Porous Silicon

The temperature effects on the photoluminescence（PL） properties of porous silicon（PS） have been observed in the early stage. However, the obtained results are different. Through repeated experiments, some different and useful information are got, which benefits us in that PL properties of porous silicon can be fully made use of. Firstly, samples with porosity of 76% and 49% were chosen to study the exciting temperature effects on the PL spectrum. For the samples with low porosity, the decreasing temperature causes the peak wavelength to be red-shifting and that of the samples with high porosity to present the blue-shifting trend. The light intensity of both reaches the maximum at - 10℃. These experimental results can be well explained with the synthesized center PL model based on the quantum confinement model, other than the PL efficiency function σ（λ）. Thereafter, PL properties of PS samples fabricated separately under the temperature of -10 ℃, 0 ℃ , 10 ℃, 20 ℃ and 30 ℃ were studied. The results indicate that with the decrease of the etching temperature, the PL intensity increases from 406.7 to 716.6 and the peak wavelength blue-shifts from 698.9 nm to 671.8 nm. The WHFM of the PL spectrum dramatically narrows. At the same time, the images observed by AFM show that with the decreasing temperature, the holes are becoming deeper and the porosity is higher, which suggests that the decreasing temperature accelerates the etching rate.     

电化学脉冲腐蚀法制备窄峰发射的多孔硅微腔

用电化学脉冲腐蚀方法制备了多孔硅微腔,讨论了脉冲电化学腐蚀的参数--周期、占空比对多孔硅多层膜制备的影响,并用了以HF酸扩散为基础的多孔硅动态腐蚀机理对实验结果进行解释,认为在用电化学脉冲腐蚀法制备多孔硅微腔的过程中,不但要考虑到HF酸对硅的纵向电流腐蚀,也要考虑到HF酸对多孔硅硅柱的横向浸泡腐蚀.可通过选取合适的周期、占空比,使二者对多孔硅的作用达到适中,以制备出高质量的多孔硅多层膜和微腔.并用正交实验法优化了制备多孔硅微腔的参数,根据优化的实验参数,制备出了发光峰半峰宽为6nm的多孔硅微腔.     

Waveguide Prism Based on Porous Silicon

The fabrication of the oxidized porous silicon waveguide prism is reported by selectively electrochemical anodisation process. The direction changes of light beams in TE and TM polarization out of this waveguide prism were respectively measured,and the experimental results were analyzed.     

基于MATLAB的硅各向异性腐蚀过程模拟

根据硅各向异性腐蚀特点,在硅各向异性腐蚀速率图基础上,提出算法,利用数学软件MATLAB模拟了几种简单掩膜图形的腐蚀过程.程序从二维掩膜描述出发,找到相关晶面,产生动态的三维几何结构的输出.并推导出凸角补偿时补偿条的相关尺寸.其结果对MEMS加工有一定参考价值.     

基于MATLAB的硅各向异性腐蚀过程模拟

根据硅各向异性腐蚀特点,在硅各向异性腐蚀速率图基础上,提出算法,利用数学软件MATLAB模拟了几种简单掩膜图形的腐蚀过程.程序从二维掩膜描述出发,找到相关晶面,产生动态的三维几何结构的输出.并推导出凸角补偿时补偿条的相关尺寸.其结果对MEMS加工有一定参考价值.     

Direct Imprinting of Porous Silicon via Metal‐Assisted Chemical Etching

Conventional lithographical techniques used for bulk semiconductors produce dramatically poor results when used for micro and mesoporous materials such as porous silicon (PS). In this work, for the first time, a high‐throughput, single‐step, direct imprinting process for PS not involving plastic deformation or high‐temperature processing is reported. Based on the underlying mechanism of metal‐assisted chemical etching (MACE), this process uses a pre‐patterned polymer stamp coated with a noble metal catalyst to etch PS immersed in an HF‐oxidizer mixture. The process not only overcomes the difficulties in patterning PS but it does so with a stamp that may be reused multiple times depending on its chemical and mechanical degradation. The process is shown to be capable of centimeter‐scale parallel 3D patterning with sub‐20 nm resolution. It is found that PS facilitates mass transport of reactants and products, and the overall etch rate is limited by local depletion of reactants. The versatility of this direct imprinting technique is demonstrated by its ability to produce curvilinear and planar 3D features (e.g., paraboloids, parabolic cylinders, sinusoidal waves, and straight sidewall channels). Miniaturized optical elements such as diffraction gratings and microconcentrators are built and characterized highlighting potential use of PS in silicon photonics.     

基于硅各向异性腐蚀的非球面微光学元件的制作

讨论了一种制作非球面微光学元件的新方法.此方法的关键步骤是将(100)硅在KOH∶H2O中的两步各向异性腐蚀.首先在硅衬底的掩模上开一组圆孔,圆孔的尺寸与最终的轮廓相对应.通过在硅衬底上腐蚀出一组凹球面状的微结构,一定的轮廓可以由一组这样的凹球面拼接而成.用这种方法可以简单高效地制作出很多用常规工艺难以加工的非球面、不规则的微光学元件.建立了描述此方法的模型,并进行了讨论分析.