【作者】 龚小刚；

【导师】 朱建国；

【作者基本信息】 四川大学 ， 凝聚态物理， 2007， 硕士

【摘要】 钽钪酸铅Pb(Sc1/2Ta1/2)O3(简称PST)是一种典型钙钛矿结构复合材料。PST铁电薄膜是一种性能优良的热释电材料,与其他材料相比,具有较高的热释电系数λ、高的电阻率ρ和大的热释电材料探测器优值FD,虽然其铁电、热释电性能很好,但由于PST居里点较低,大致在-5~25℃、且需要在相当高的温度下(1500℃)才能合成致密、具有钙钛矿结构、性能良好的PST材料,因此,这个条件极大制约了PST材料的应用。如在PST中加入钛酸铅(PT,其居里点约为490℃),形成具有符合钙钛矿结构的(1-x)PST-xPT固溶体,可以较大幅度地提高PST材料体系的居里点、降低其制备温度,从而扩大PST材料体系的应用范围。本论文采用了普通电子陶瓷法制备了纯钙钛矿的PSTT靶材,用RF磁控溅射法制备了PSTT铁电薄膜,并研究了衬底、基底温度、退火温度、退火方式等工艺参数对其结构和性能的影响。同时也制备了PZT80、PZT20陶瓷靶,对PZT80、PZT20交替多层薄膜进行了部分研究,所得主要结论如下:1、在LSCO/Pt/Ti/SiO2/Si上沉积的PSTT薄膜为纯钙钛矿相,结构比较致密。大气气氛下,分别在700℃、750℃快速退火2min的PSTT薄膜样品,为(220)高度取向。2、725℃快速退火3min的PSTT薄膜样品的剩余极化强度Pr为2.12μC/cm2,矫顽场Ec为59.35kV/cm。介电常数和损耗分别为492、0.0046。3、700℃快速退火3min后的PSTT薄膜样品,在偏压为15V时,漏电流密度小于10-6A/cm2。725℃快速退火3min后的PSTT薄膜样品在偏压为13V时,漏电流密度也接近10-6A/cm2。4、在频率从0.5~150kHz时,四方相厚度dR和三方相厚度dT的比率dR/dT为1:3的PZT多层薄膜介电常数和损耗分别为328,0.0098,其剩余极化强度Pr为32.6μC/cm2。更多还原

【Abstract】 Lead scandium tantalite Pb(Sc1/2Ta1/2)O3(PST) is a kind of the typical composite perovskite structure materials. Compared to other materials, PST ferroelectric thin films possess superior properties such as high pyroelectric coefficientλ, high resistivityρand big figures of merit of pyroelectric material detector FD. Though it has excellent ferroelectric and pyroelectric properties, however, PST with dense perovskite structure and good properties can only be synthesized and prepared under quite high temperature (1500℃), and due to its low Curie point (approximately -5~25℃) , the applications of PST had been substantially limited. If lead titanate (PT, its Currie temperature of about 490℃) is added into PST materials to form (1-x)PST-xPT solid solution with composite perovskite structure, it can significantly improve Currie temperature of PST material system, reduce its preparation temperature, and thus extend applications of PST material system.In the paper, the common electronic ceramics method was employed to prepare pure perovskite PSTT target and RF magnetron sputtering method was employed to prepare PSTT ferroelectric thin films. Then effects of processing parameters such as different substrates, substrate temperature, annealing temperature and annealing method on the properties of PSTT thin films were studied. At the same time, PZT80 and PZT20 targets were also prepared, and the alternate multiplayer films of PZT80 and PZT20 were partially studied. The major conclusions are as follows:1. PSTT thin films deposited on LSCO/Pt/Ti/SiO2/Si show the pure perovskite phase and rather dense. Under atmospheric conditions, PSTT thin film samples annealed at 700℃and 750℃for 2min by using rapid thermol annealing, show (220) high orientation.2. PSTT thin film samples annealed at 725℃for 3min, by using rapid thermol annealing have remanent polarization Pr of 2.12μC/cm2 and coercive field Ec of 59.35 kV/cm, permittivity of 492 and dielectric dissipation of 0.0046.3. PSTT thin film samples annealed at 700℃for 3min have leak current density less than 10-6A/cm2 at bias voltage of 15V; PSTT thin film samples annealed at 725℃for 3min have leak current density close to 10-6A/cm2 at bias voltage of 13V.4. In the frequency region from 0.5~150 kHz, the permittivity dielectric and dissipation of PZT multilayer films with dR/dT of 1:3 are 328 and 0.0098 respectively; and its the remanent polarization Pr is 32.6μC/cm2.更多还原