非制冷型热释电薄膜红外探测器的制备及应用

介绍了室温非制冷型热释电薄膜红外探测器的原理和优势。从热释电材料的选择及器件的结构设计等方面阐述了热释电薄膜红外探测器的制备技术和研究动向,并归纳了器件的主要应用领域。     

柠檬酸溶胶-凝胶法制备非晶YBCO薄膜

采用柠檬酸溶胶-凝胶法(Pechini工艺)制备了钇钡铜氧(YBCO)溶胶,在SiO2/Si(110)衬底上生长了非晶YBCO薄膜.通过差热-热重分析得到了非晶YBCO薄膜的热处理务件.讨论了pH值对薄膜元素配比和表面形貌的影响,研究了薄膜结晶状态与退火温度之间的关系,获得了较为理想的薄膜制备工艺参数.     

用旋涂法制备的热释电聚合物薄膜研究

PVDF聚合物热释电薄膜是一种新的激光与红外辐射探测器材料,它比无机薄膜更易于与硅微加工工艺为基础的硅读出电路兼容.本文用旋涂法制备了一种聚合物热释电薄膜,对其进行了红外光谱和X射线衍射分析,并研究了其热释电响应特性,结果表明与其他方法(流延法和压膜法)相比,旋涂法制备的聚合物薄膜样品对热响应具有更高的灵敏度,更适合用作激光与红外辐射探测器材料.(PH2)     

钛酸锶钡热释电薄膜及其非制冷红外探测器研究

开展了钛酸锶钡(BST)热释电薄膜材料制备工艺研究,及其在单元器件和焦平面器件中的应用研究.在删Pt/Ti/SiO2/Si衬底上,用倒筒靶射频溅射方法制备了BST热释电薄膜.通过低温缓冲层技术和调控自偏压的方法,降低了BST薄膜的生长温度,提高了BST薄膜的c轴取向度和耐压特性,解决了薄膜制备的均匀性和一致性问题,使薄膜热释电系数达到6.7×10-7Ccm-2K-1.利用微细加工的方法,制备出全集成的BST薄膜单元红外探测器,抗过载能力强,探测器达到8×107cmHz1/2W-1,可以满足"灵巧弹药"的使用要求.实验表明,制备BST热释电薄膜的工艺不会对新型的耐高温读出电路造成破坏,为研制高性能的BST薄膜型焦平面探测器奠定了基础.     

薄膜型热释电红外探测器的发展

介绍了薄膜型热释电红外探测器的性能特点和工作原理。从材料选择,器件结构和制备工艺综述了近几年国内外的研究成果及发展动态,并对器件的主要应用进行了总结。     

PLCT系列热释电薄膜的最新研究进展

热释电红外探测器广泛应用于辐射测温，红外光谱测量，安全警戒，红外热成像等领域。掺杂钛酸铅薄膜是性能优异，应用广泛的热释电薄膜，文章主要介绍了镧，钙双掺的钛酸铅薄膜的性能。比较了不同组分的PCT、PLT、PLCT铁电材料的制备方法、结晶性、铁电性、介电性及热释电性能与分组的关系，并对PLT系列热释电薄膜材料的应用前景作了探讨。     

复合热释电薄膜红外探测器的研究

热绝缘结构是热释电红外探测器的关键技术之一."复合热释电薄膜红外探测器"是用多孔SiO2薄膜来绝热的,这种无空气隙的新型结构被认为具有更高的机械强度和可靠性.采用溶胶-凝胶技术制备了热导率极低的多孔SiO2薄膜,用金属有机物热分解法制备了优质的铁电薄膜,实现了"复合热释电薄膜"热绝缘结构,获得的星探测率最大值达9.3×107cm.Hz1/2/W.通过快速热处理工艺的采用,提高薄膜一次成膜厚度的研究,改善了薄膜制备与微电路工艺的兼容性.研究了多孔膜厚度、孔径分布与探测率的关系,探讨了镍酸镧(LNO)薄膜作为缓冲层、红外吸收层和上电极的多功能作用.结果表明:孔径分布小的多孔膜有利于探测器性能的提高.在此结构中,存在热性能和电性能的折中问题,多孔膜厚度有一个临界值.LNO薄膜的引入,可以改善性能、简化结构和工艺.讨论了低温铁电薄膜的制备和性能,以及与微电路实现单片集成等问题.     

薄膜型热释电探测器红外响应模型分析

在进行热释电焦平面探测器ROIC（读出电路）设计时,必须充分考虑热释电探测器的红外响应特性,并根据探测器等效电路的SPICE模型进行设计仿真。从热释电探测器的热平衡方程出发,在Matlab平台上分析模拟了探测器对脉冲函数调制状态下的瞬态响应,并根据提供的薄膜材料参数在具体应用中建立了热释电探测器的等效电路模型。把探测器等效电路模型与SFD（源跟随器）型输入单元读出电路连接后进行模拟仿真,分析了不同条件下热释电探测器／读出电路组件的响应特性。     

热释电薄膜在红外探测器中的应用

介绍了热释电效应及热释电薄膜红外探测器的工作模式,特别是探测器单元对热释电薄膜的材料与低温生长要求。为了克服薄膜生长过程中较高的基片温度对读出集成电路(ROIC)的破坏性影响,一方面发展了离子束辅助沉积、外延缓冲层等多种低温生长技术,另一方面发展了复合探测器结构设计。已研制出了性能良好的铁电薄膜非制冷红外焦平面阵列,其噪声等效温差(NEDT)可达20mK。     

非制冷红外探测器用热释电材料的研究进展

分析了热释电非制冷红外探测技术的优势,介绍了当前应用较广泛的各种非制冷红外探测器用热释电材料,即单晶材料、高分子有机聚合物及复合材料和金属氧化物陶瓷及薄膜材料,并预计了热释电材料的发展趋势.指出了铁电性热释电陶瓷材料的优越性,其应用分为正常热释电体、介电测辐射热型热释电体和弥散相变热释电体,并分别列出了具有代表性材料的研究结果.最后,指出了研究高性能、大尺寸、易加工的热释电薄膜材料的制备技术,是未来红外探测器用热释电材料的发展的关键;并在此基础上结合半导体集成3-艺,制备高性能、大规模的热释电红外焦平面阵列.     

朗缪尔铁电聚合物薄膜的电学特性:高热释电系数和低介电常数

研究了利用朗缪尔技术(LB)生长在柔性基底上的聚偏氟乙烯和三氟乙烯的共聚物(P(VDF-TrFE))薄膜的电学性质.通过测量相对介电常数和热释电系数,发现薄膜在室温1kHz时的优值因子达到1.4 Pa~(-1/2).这表明利用LB技术生长的P(VDF-TrFE)薄膜是热释电探测器的优良候选材料.优值因子的提高可能来源于LB薄膜的良好结晶性和分子链在平面内的高度有序性.     

Nanosecond detector of infrared radiation based on thin pyroelectric films

The features of detection of short radiation pulses by thermal detectors based on thin pyroelectric films with the radiation energy deposited in a thin absorbing electrode are considered. It is demonstrated that the minimum response time of the sample to radiation pulses is determined by the time of thermal relaxation of the absorbing electrode. Specifically, picosecond pulses may be detected with a 0.5-μm-thick pyroelectric film and a 0.01-μm-thick absorbing electrode.     

Pb（Zrx，Ti1-x）O3成分梯度铁电薄膜的制备、结构及电性能表征

采用Sol-Gel方法,通过快速热处理,在Pt/Ti/SiO2/Si衬底上制备出Pb(Zrx,Ti1-x)O3成分梯度薄膜.经俄歇微探针能谱仪(AES)对制备的"上梯度"薄膜进行了成分深度分析,结果证实其成分梯度的存在.经XRD分析表明,制备的梯度薄膜为四方结构和三方结构的复合结构,但其晶面存在一定的结构畸变.经介电频谱测试表明,梯度薄膜的介电常数比每个单元的介电常数都大,但介电损耗相近.在10 kHz时,上、下梯度薄膜的介电常数分别为206和219.经不同偏压下电滞回线的测试表明,上、下梯度薄膜均表现出良好的铁电性质,其剩余极化强度Pr分别为24.3和26.8 μC·cm-2.经热释电性能测试表明,热释电系数随着温度的升高逐渐增加,室温下上、下梯度薄膜的热释电系数分别为5.78和4.61×10-8 C·cm-2K-1,高于每个单元的热释电系数.     

Phase composition of films in a Bi-S system and formation of Bi<Subscript>2</Subscript>S<Subscript>3</Subscript> films with different substructures

Electron diffraction was used to study the formation of phases in a Bi-S system. It is shown that the phase with composition Bi₂S₃ appears as result of consecutive deposition of Bi and S irrespective of the order of deposition; this phase also appears in the case of simultaneous deposition of components. The films formed at room temperature are amorphous. Amorphous thin Bi₂S₃ films are stable at room temperature and crystallize at temperatures in the region of ～423 K. The conditions for formation of Bi₂S₃ films with different substructures are established.     

Pyroelectric detection properties of gadolinium molybdate (gmo)

The pyroelectric detection properties of gadolinium molybdate (GMO) crystals have been studied near and at its 159°C ferroelectric transition temperature. Responsivity and detectivity figures of merit are calculated from measurements of pyroelectric currents induced by white light irradiation and are compared with room temperature figures of merit for TGS and SBN detectors. Since GMO does not exhibit a dielectric anomaly, it can be used as a threshold detector by heating through the transition temperature from a pre-selected temperature increment below the transition. Voltage-sensitive pyroelectric currents at the transition, found previously, permit voltage control of the threshold.     

Room Temperature Bolometric Applications Using Manganese Oxide Thin Films

We report the optical responses of magnetic manganese oxide La_2/3Ca_1/3MnO_δ thin films at room temperature. The voltage responses to a He-Ne laser at the wavelength of 0.63 μm and incident infrared (IR) power at the wavelength of 8-14 μm were measured. The measured signals were attributably to a bolometric response due to the heating of the sample by radiation. We report the optical responses in La_2/3Ca_1/3MnO_δ thin films as a function of chopping frequency and bias current. The noise behavior around room temperature was also discussed. It is suggested that perovskite manganese oxide thin films are suitable candidates for uncooled optical detectors.     

Millimeter wave detectors using the pyroelectric effect

Experimental work conducted on pyroelectric detectors in the microwave and millimeter wave regions show that the response time of such a device utilizing TGS at room temperature is on the order of 40 ns. An analysis is presented which shows good agreement with the experimental results for both long and short duration pulses. Observing the pyroelectric response also provides a direct measure of the thermal conductivity of the material. Our estimated value for TGS at room temperature is9.1 times 10^{-5}cal/cm.s.°C.     

α-SiO_xN_y薄膜中分立能级的光发射

采用 PECVD法制备了 α- Si Ox Ny 薄膜 ,观察到两组分立能级的强荧光发射 ,一组位于紫外光波段 ,由三个可分辨的发射峰组成 ,波长分别为 330、340和 345nm;另一组位于红光波段 ,由两个发射峰组成 ,波长分别为 735nm和 745nm.发射峰依赖于薄膜中氧和氮的同时存在 ,其强度首先随薄膜中其含量的增加而增强 ,达到饱和值后 ,随着其含量的进一步增加而下降 .这表明发射峰可能起源于 O- Si- N结合而形成的发光中心 .