离子束增强沉积制备钽酸锂薄膜电性能分析

为提升钽酸锂薄膜的性能,提出一种离子束增强沉积法制备钽酸锂薄膜的新工艺。分别采用这种新工艺和溶胶-凝胶法制备了钽酸锂薄膜,并利用阻抗分析仪和铁电材料分析仪对制备样品进行了介电性能、铁电特性、漏电电流和热释电特性分析。实验结果表明,采用离子束增强沉积制备的钽酸锂样品经550℃退火后,介电常数为39.44,介电损耗为0.045;测试电场强度为400kV/cm时,漏电流为4.76×10-8 A/cm2,击穿场强为680kV/cm,热释电系数达到1.82×10-4 C/m2 K。相比之下,采用溶胶-凝胶方法制备的钽酸锂薄膜样品,其介电常数、介电损耗、漏电流都更大,击穿场强和热释电系数更低。从电性能参数比较可以看出,离子束增强沉积法比溶胶-凝胶法更适合用于制备钽酸锂薄膜。     

新型铁电薄膜底电极TiN的结构与电性能研究

自制了导电的TiN薄膜底电极,并在其上制备了铁电钽酸锂薄膜,测试了TiN薄膜电阻随热处理温度变化的关系,以及TiN底电极上钽酸锂薄膜的介电和漏电特性.实验结果表明,当热处理温度低于700℃时,TiN薄膜的电阻率小于0.004QΩ·cm,具有良好的导电性,可用作钽酸锂薄膜底电极;TiN底电极上钽酸锂薄膜的漏电电流大于Pt衬底上钽酸锂薄膜的漏电电流;N2气氛下在TiN底电极上结晶的钽酸锂薄膜的介电损耗远大于O2气氛下结晶的钽酸锂薄膜的介电损耗;氧缺位是TiN底电极上钽酸锂薄膜介电损耗大和漏电大的主要原因.     

PbSc0.5Ta0.5O3热释电材料及其红外探测器列阵

热释电红外探测器具有探测波长范围广、室温工作、无需致冷等优点。近年来，工作于介电方式下的PbSc0.5Ta0.5O3(PST)热释电材料由于具有热释电系数大，热释电探测优值高等特点，成为热释电应用研究的热点之一。本文综述了目前PST热释电陶瓷材料的介电，热释电性能及其探测器列阵的发展。由于小型化的要求，PST薄膜亦倍受关注，因此本文还对目前PST热释电薄膜的制备方法，薄膜的热释电、介电性能及薄膜型探测器结构和发展进行了概述。     

利用新设计磨具对铌酸锂晶片的减薄及减薄后的测试

铌酸锂晶体具有较强的热释电效应,由铌酸锂制作的红外传感器敏感头受到科研人员的广泛关注。将晶片与硅衬底在200°C和压力100N的条件下键合,利用自行设计的磨具将铌酸锂减薄到40微米,磨料由水与刚玉以1∶1的比例制成。本文讨论了铌酸锂键合的过程,减薄的过程及厚度测试,通过拉曼光谱分析残余应力,通过原子力显微镜测试样品表面粗糙度。研究结果表明,通过自行设计的磨具研磨的晶片厚度最大差值7微米,较为均匀;研磨后晶片表面粗糙度为118纳米,较为粗糙;键合后存在一定的残余应力。制作好的铌酸锂晶片符合制作红外传感器敏感头的要求。     

新型PST铁电薄膜的制备及其电性能研究

PST铁电薄膜是一种具有优良铁电、热释电和介电等性能的铁电材料.该材料在红外探测器、红外焦平面阵列、热成像器件、非易失性铁电存储器和大容量电容器等方面具有广泛的应用.PST铁电薄膜的制备方法多种多样,各具优缺点,不同的制备工艺对薄膜的性能有影响.叙述了PST铁电薄膜的制备技术、电性能和在热释电红外探测器方面的应用.     

提高热释电红外感应器灵敏度的分析与对策

热释电红外传感器是一种被动式调制型温度敏感器件,利用热释电效应,通过目标与背景的温差来探测目标。热释电红外传感器在电子防盗、人体探测器领域中,应用很广泛,通过分析热释电红外传感器输出信号的特性,着重通过提高热释电感应器的性能来提高传感器的灵敏度。     

铁电薄膜的制备及应用技术研究

研究出具有特色的制备铁电薄膜的 sol-gel技术;制备出高质量、高可靠的 PLT、PZT、PYZT、BST”l、PbTiO3、BaTiO3、Bi4Ti3O12多晶铁电薄膜,PLT、PZT和伽里O3异质外延生长铁电薄膜;研制出铁电薄膜热释电单元红外传感器,8元、9元、1O元线列和8X8元阵列;研制出热释电火情探测器和热释电非接触式温度测试仪。     

基于超薄钽酸锂晶片及炭黑红外吸收层的热释电探测器

基于钽酸锂(LiTaO3)的热释电探测器具有灵敏度高、热释电系数大、响应范围宽等优点而被广泛应用于非分光红外气体检测.在LiTaO3热释电探测器制备过程中,采用预置沟槽方法制备出约20μm厚的超薄LiTaO3晶片,该方法既能控制晶片厚度又能实现自动解片,简化了探测器制备工艺;采用电喷雾方法制备出炭黑红外吸收层,该方法工艺简便,制备的吸收层分布均匀,结构疏松.电喷雾时间为20 min时制备的吸收层在常用气体吸收波段(2.5~10μm)的红外吸收率达98%以上,使探测器信号幅值提高了约2.6倍.热释电探测器性能测试结果表明:单元结构探测器的黑体探测率可达1.78×108cm·Hz1/2/W;二元补偿结构探测器信噪比为单元器件的2倍;将二元补偿结构探测器应用于非分光红外气体测试系统,进行了SO2气体检测,等噪声检测下限约为1×10-6.     

红外探测用陶瓷材料研究的最新进展

本文根据热释电红外探测器对材料性能的要求,综述了国外热释电陶瓷材料研究的现状和发展。并介绍了作者用溶胶-凝胶法制备(Pb,Lb)TiO_3陶瓷薄膜近期的研究结果。     

其它领域中的新材料相关项目

1、电子专用材料 我国电子专用材料产业已形成一个门类比较齐全、产业规模较大的行业。但硅材料、框架材料、电子陶瓷及氧化铟大型靶材等电子工业所急需的专用材料大部分仍需要从国外进口。近年来,我国在电子专用材料的开发和生产方面巳具备一定基础。近期产业化的重点是:高性能软磁铁氧体材料及所需的高纯度原材料（Fe2O3和Mn3O4）,高比容钽粉,细径锃丝,高性能电子浆料,大功率压电陶瓷和热释电陶瓷材料等功能陶瓷材料,氧化铟锡大型靶材,高性能液晶材料,超净高纯化学试剂,电子特种气体,3英寸以上铌酸锂和钽酸锂单晶,光刻多     

溶胶凝胶钽酸锂薄膜热释电红外探测器的设计与制备

在带微桥结构的石英玻璃基底上设计了一种新型Al-LiTaO3-ITO红外探测结构。在响应/参考双单元结构框架下,由振动、环境温度变化和日照变化引起的无效信号输出在前置放大电路处被消除掉了。用醋酸锂和乙醇钽作为起始反应物,通过溶胶凝胶工艺生成了对红外敏感的钽酸锂薄膜,并详细讨论了基于钽酸锂薄膜的红外探测器件制备工艺。用ITO衬底作下电极,蒸镀的Al点作上电极,在室温条件下测试了薄膜的介电特性,在1kHz处,介电常数为53.28,在40~10kHz内,介电损耗和介电系数呈下降趋势。器件的电压响应和比探测率测试结果表明75Hz处得到响应电压峰值9685V/W,器件的比探测率在70~100Hz区域保持在6.12×108cmHz1/2W-1附近。     

Absolute linearity measurements on LiTaO3 pyroelectric detectors

The nonlinearity characteristics of a number of LiTaO3 pyroelectric detectors were experimentally investigated using the National Physical Laboratory (NPL) detector linearity characterization facility. All the detectors examined were shown to exhibit a superlinear response, i.e., the responsivity of the detectors increases as the incident radiant power increases. The temperature coefficient of response of some of these LiTaO3 pyroelectric detectors was measured and found to be approximately +0.2% degrees C(-1). The superlinear behavior of the LiTaO3 pyroelectric detectors was attributed to the positive temperature coefficient of response values of these detectors. Moreover, the linearity factor of gold-black-coated LiTaO3 pyroelectric detectors was shown to exhibit a dependency on the area of the spot illuminating the active area of the detector, i.e., on the incident irradiance. Possible reasons for the observed behavior are proposed and discussed. Some variations in the slopes of the plots of the linearity factor versus irradiance for different areas being illuminated have been assigned to the poor spatial uniformity of response of these detectors.     

Switching transient analysis of a metal/ferroelectric/semiconductor switch diode with high speed response to infrared light

A thin PbTiO(3)-n-p(+) silicon switch diode has been developed, in which the switching voltage (the turned-on voltage) changes in proportion to the infrared light power. The diode has a rapid response time of 0.65 mus compared with other conventional infrared sensors. It is attributed to the rapid switching device structure and the smaller pyroelectric layer thickness, 50 nm. In this paper, we have analyzed the rapid switching transient response by using heat conduction and switching theory successfully. The experimental results are in agreement with the theoretical analysis.     

Novel pyroelectric sensor materials

Ceramic compositions of barium strontium titanium oxide (BSTO) have been formulated for applications as pyroelectric sensor materials. The material has been fabricated in tape-cast and thin film forms. In general, the materials demonstrated high pyroelectric coefficients (p) accompanied with low dielectric constant and low dissipation factor. The compositions of the tape-cast and thin film specimens examined in this paper include a well-known commercially adopted Ba_0.64Sr_0.36TiO₃ as well as a composition suggested in the literature, and a patented composition with the addition of MgO to BSTO is investigated. Doping BSTO with MgO has been shown to reduce the dielectric constant and loss tangent (over a very wide frequency range from 100 Hz-10 GHz) of the material and thereby increase the pyroelectric figure of merit. This article will discuss the processing, material characterization, pyroelectric coefficient, and pyroelectric figure-of-merit of the above mentioned BSTO compositions.