【作者】 张洁；

【导师】 王连卫； 徐少辉；

【作者基本信息】 华东师范大学 ， 微电子与固体电子学， 2008， 硕士

【摘要】 多孔硅光子晶体(Porous Silicon Photonic Crystal)是一种新型光学功能材料,通常采用阳极氧化法(Anodization)制备,阳极氧化在单一方向上进行且高低电流密度周期交替变化可以构成不同孔度的多孔硅在一维空间上的周期交替排列,即造成了不同介电常数层的周期性排列,这种多层结构可形成类似于半导体中电子能量带隙的光子频率带隙(PBG,Photonic Band Gap),故称为一维光子晶体(1-Dimension Photonic Crystal),频率在某一带隙内的电磁波无法传播到光子晶体的另一端,这种制作薄膜的方法相对简便、制作成本非常低、具有孔度可调制等独特性质,使多孔硅成为一种在光学应用领域非常具有潜力的材料。如果氧化后的多孔硅一维光子晶体的“光子带隙”被设计在热释电传感器的信号波段,它的隔热性能可用于热释电传感器衬底从而提高探测器的灵敏度,同时又能对特定红外波段辐射实现阻断。热释电红外传感器因其灵敏度高、工作于常温下,长久以来成为红外研究的热点,近年来有很多研究致力于提高其综合性能,其衬底的绝热结构和红外辐射的阻断方式构成了影响非制冷红外焦平面探测器阵列的分辨率和探测率等性能提高的主要因素。本论文研究其衬底材料,希望采用氧化后的多孔硅一维光子晶体来构建热释电红外传感器的新型衬底。本文通过计算机模拟讨论了结构参数对光子晶体多层膜结构光学质量的影响,利用阳极氧化法形成多层膜结构,通过快速热氧化制备绝热性能优越且光子频率带隙位于中远红外波段一维光子晶体,并讨论和改进工艺因素以优化性能,利用这种材料探索非制冷红外焦平面探测器阵列的衬底。论文第一章扼要地阐述光子晶体和非制冷红外热释电探测器的概念,介绍目前基于多孔硅的一维光子晶体发展现状以及存在的主要问题,并分析本论文立题依据、可行性和独特前沿性。论文第二章论述基于多孔氧化硅一维光子晶体的制备方法。探讨电流密度、电解液、腐蚀时间和温度、快速热氧化时间和温度等实验参数对其结构、性能的影响。论文第三章采用传输矩阵的方法对多孔硅一维光子晶体的光学结构参数进行了讨论,并分析周期数、折射率之比和中心波长对禁带的影响。论文第四章论述多孔硅一维光子晶体的处理和优化,介绍和分析氧化前后的傅立叶转换红外线光谱(FTIR)移动变化及与MATLAB拟合的结果对比并分析形成光子带隙的条件,并成功制备中心禁带位于中红外波段(5、6、7微米)具有良好绝热性能多孔氧化硅一维光子晶体,并探讨工艺改进方案。论文第五章论述对制备光子频率带隙位于远红外波段(10微米)一维光子晶体研究意义及傅立叶转换红外反射谱的实现与讨论,并对多孔氧化硅作为制作非制冷红外焦平面探测器阵列的衬底进行探索与实现,采用SEM对其多层膜结构进行了验证并成功地得到禁带中心位于10微米的高反射光学性能。论文第六章对全文工作进行总结,并对基于多孔氧化硅制作非制冷红外焦平面探测器阵列的衬底进行应用展望。更多还原

【Abstract】 Porous Silicon,a brand new optical material,is usually fabricated by anodization. Periodically alternative changes of high/low current densities may form alternative porosities in anodization in one dimension.Therefore,it consists of alternating layers of different refractive indices,resulting in considerable novel characters named photonic band gap(PBG),which means the light can’t transmit in the photonic crystal when light’s frequency locates in the PBG.Thus,it is also called 1-Dimension photonic crystal.Large refractive index variation with porosity,as well as relatively simple fabrication and low manufacturing cost,makes porous silicon a very promising candidate for photonic applications.Since after oxidation,the porous silicon can be oxidized into one of excellent thermal isolative properties,if its photonic band gap is designed at the mid/far infrared(IR)wavelength,this porous structure can be used as the substrate for non-cooling infrared pyroelectric thin film IR detector,which can not only block the radiation for mid-IR but also can isolate the heat.Non-cooling infrared pyroelectric thin film IR detector has attracted great interest due to its high sensitivity and can be applied at room temperature. Unfortunately,the thermal isolative structure of the substrate and its infrared radiation was the major factors that limit the resolution of non-cooling infrared pyroelectric thin film IR detector.This thesis focuses on this problem and tries to find a substrate material for non-cooling infrared pyroelectric thin film IR detector, based on the oxidation of one dimension porous silicon photonic crystal.The structure factors of the PBG material is discussed,which can influence the photonic crystal multilayer through computer simulation and be referenced for the anodization process.Rapid thermal oxidation(RTO)is applied to achieve a good thermal isolative layer with a photonic band gap at expected mid/far infrared range. Several factors have been discussed to optimize the properties to get a substrate for non-cooling infrared pyroelectric thin film IR detector.In ChapterⅠ,the basic knowledge of photonic crystal is introduced briefly, especially one dimension photonic crystal together with the development status of photonic crystal and the problems it has encountered.The aim of this paper is also listed.In ChapterⅡ,the basic theories and fabrication technique are described for the one dimension porous silicon photonic crystal.The influence of the factors,such as current density,HF concentration,the type of substrate,formation temperature and RTO time and temperature are discussed to obtain the promising substrate material.In ChapterⅢ,one dimension porous silicon photonic crystal is designed by means of the transfer-matrix method(TMM).The influence of the number of periods and the ratio of refractive indices are investigated on the wavelength of mid-gap to the reflectivity spectra.In ChapterⅣ,the optimization of one dimension porous silicon photonic crystal is discussed.Fourier transform infrared spectroscopy(FTIR)is applied to check the difference before and after oxidation,contrast and comparison with simulation.Parameters for obtaining photonic crystals with the PBG gap ranging in mid(5、6、7 microns)have been successfully achieved.Such a material has also good thermal isolative properties due to RTO process.In ChapterⅤ,the practical use of the substrate at far-IR(10 microns)is discussed and the fabrication procedure of the array for non-cooling infrared pyroelectric thin film IR detector has been addressed and achieved.SEM is applied to find its multilayer structure while FTIR for its optical properties.ChapterⅥwill summarize the work and discuss the future application for this promising substrate.更多还原