【作者】 冯冲；

【导师】 唐祯安； 余隽；

【作者基本信息】 大连理工大学 ， 电路与系统， 2013， 博士

【摘要】 近场热辐射是当前国内外的一个研究热点。研究微纳器件中的近场热辐射对提高器件的绝热性能和开发新型器件都有重要的意义。本文开展了对微纳器件中近场热辐射现象及其测试技术的研究,并通过研制微纳米间隙分隔的、自对准的双层悬空微热板新型器件(简称双微热板器件),实现了平行二氧化硅(Si02)平板间近场辐射传热的实验测量。本文内容涵盖了对微纳器件中近场热辐射的理论研究,双微热板器件的设计和制作、双微热板器件的特性参数测试及其近场辐射传热的实验测量。首先,进行了微纳器件中近场热辐射的理论研究,并建立了实验模型。利用涨落耗散原理描述物质内部的涨落电流,利用格林函数法求解频域麦克斯韦方程,得到涨落电流辐射的电磁场,通过计算电磁场坡印廷矢量的系综平均值,给出了平行平板间辐射传热的计算方法。在此基础上,建立了平行Si02平板间近场辐射传热的实验模型,获得了Si02平板间距在1μm或更小时其间近场辐射传热显著增强的仿真结果。因此,选择平板间距分别为550nm和1μm两种情况进行实验测量。这一研究工作为双微热板间距的设计提供理论依据,所得研究数据可供微纳器件设计人员参考。其次,研究了双微热板器件的设计及加工技术。基于表面微加工技术设计双微热板器件的加工流程,利用独特的双层牺牲层技术,通过研制自对准的双层悬空薄膜结构,实现双微热板器件的制作。基于上华0.5μm CMOS数模混合集成电路工艺设计加工了两层微热板间距为550nm的双微热板器件；基于定制的MEMS工艺设计加工了两层微热板间距为1μm的双微热板器件。在上述工作中,通过探索合理的工艺流程,研究并解决了在器件加工过程中的腐蚀窗刻蚀、牺牲层腐蚀、牺牲层腐蚀完成的辅助判断和结构层薄膜残余应力控制等若干关键技术,实现了双微热板器件的加工,提高了加工成品率。再次,组建了双微热板器件性能参数测试系统。该系统由真空系统和计算机采集控制器部分组成。在真空(10-7mbar)、环境温度293K的条件下,对器件中每层微热板的最大加热电流和热延迟时间,以及两层微热板之间的绝热性进行了测试,得出双微热板器件的特性参数。最后,完成了双微热板间近场热辐射的测试。测试中,采用恒电流方式加热下层微热板作为热辐射的发射器,上层微热板作为吸收器,通过测定吸收器的温升与其吸收热功率的关系,以及比较有无上层吸收器时,下层发射器达到相同温度的加热功耗差值,实现对两层微热板间近场辐射传热的测量。对于间距分别为550nm和1μm两种样品,所测近场辐射热导与文献中的近场辐射热导数值相近。表明本文提出的测试技术能实现对微纳器件中近场辐射传热的实验测量,为相关研究提供了新途径。更多还原

【Abstract】 The research on the near-field thermal radiation attracts many focuses recently. The study on the near-field thermal radiation in micro devices is important to improve the thermal insulated property of micro devices and develop new micro devices. Based on developing a novel device with self-aligned double suspended mciro-hotplates separated by a micro-nano gap (DMHP for short), the experimental measurement technology of the near-field thermal radiation in micro devices is studied in this thesis. By using DMHP, the near-field thermal radiation of silicon oxide was systematically investigated. The main contents of this thesis include the theoretical research of near-field thermal radiation, the design and fabrication of DMHP, the characteristic parameters measurement of DMHP and the experiment measurement of the near-field thermal radiation.Firstly, the micro mechanisms of thermal radiation were researched and a model was formed. The electromagnetic field of the thermal current was calculated by describing the spatial correlation function of the thermal current fluctuations based on the fluctuation-dissipation theorem and Maxwell’s equations solved by green’s function method. By taking an ensemble average on the Poynting vector, a calculation method of the near-field radia-tive heat transfer between two semi-infinite planes was given. Then, a model of near-field radiative heat transfer between two silicon oxide plates was formed. We obtained that the near-field thermal radiation is significantly enhanced while the distance between two silicon plates is less than1μm. So the near-field thermal radiation between two SiO2plates separated by the distances of550nm and1μm are chosen to study in this thesis. This work not only presents a theoretical basis for DMHP design, but provides reference data for related researchers.Secondly, the technologies of design and fabrication of DMHPs were investigated. Based on surface micromachining technology, the process flow of the two types of DMHP were designed. By using double sacrificial layers, the self-aligned double freestanding membranes of a DMHP were fabricated. By using CSMC0.5μm CMOS technology, a CMOS DMHP was developed, which the gap between the two freestanding membrane of the device is550nm; by using a customized MEMS (MicroElectroMechanical Systems) technology, a MEMS DMHP was developed, which the gap between the two freestanding membrane of the device is1μm. The appropriate manufacturing processed were designed, with many key technics were researched and solved, including window etching,sacrificial layer wet etching, the Auxiliary structure for judging the end of sacrificial layer etching and residual stress control of thin films. So, the output capacity was guaranteed.Thirdly, the performance testing system of DMHP were built up. First, we built the system above with a vacuum system and a computer. Then, under the conditions of the ambient temperature293K and vacuum (10-7mbar), the heating current limit of each micro-hotplate of DMHP, the thermal insulation performance of the two micro-hotplates and the thermal delay time of each micro-hotplate of DMHP were tested. The works above provide the necessary parameters for DMHP’s applications.Finally, experimental measurements of the near-field radiative heat transfer between two micro-hotplates was carried out. In these experiments, the bottom micro-hotplate was heated by constant currents and worked as a heat emitter, the top micro-hotplate worked as a heat absorber, the near-field thermal radiative heat transfer between the two micro-hotplate of DMHPs were evaluated by calibrating the relationship between the temperature rising and heating power of the absorber, and by detecting the heating power difference between heating the emitter to the same temperature before and after removing the absorber. For the cases that two SiO2plates separated by the distances of550nm or1μm, the measured values of thermal conductance of near-field thermal radiation are similar with others. The results above indicate the test technology brought forward in this thesis can be applied for investigating the near-field thermal radiation happened in micro-nano devices, and provide a new method for the measurement of the near-field thermal radiation.更多还原