用变速提拉新技术生长无散射颗粒的铌酸锂晶体

为了提高LiNbO3晶体的光学质量,必须克服晶体中的散射颗粒.本文在研究LiNbO3晶体中固体散射颗粒的基础上,提出了变拉速技术,并用于同成份LiNbO3晶体的提拉实验,取得了成功,不仅克服了晶体中的散射颗粒,而且晶体的单轴性也有提高.用变拉速技术生长出的同成份LiNbO3晶体用于电光Q开关,效果很好.     

LiNbO3:Mg2+晶体的生长条纹和散射颗粒

本文研究了LiNbO3:Mg2+晶体各种掺杂浓度时的生长条纹和散射颗粒,测定了它们对晶体质量的一些影响,用激光探针法鉴定了固体散射颗粒的成份,并讨论和总结了这两种缺陷的成因和克服办法。     

电阻炉Nd∶YAG晶体的散射损失和消光比

研究了影响晶体激光效率的几个因素。结果表明,散射颗粒影响最大。按其多少粗略分成五级,可大体反映效率高低。由一个激光作光源的大角散射测量装置测量散射损失。散射损失与激光效率对应关系趋势明显。本文还报导了有关消光比情况及退火消除色心的效果。     

电阻炉内气氛对Nd:YAG晶体中散射颗粒的影响——对充入适量CO_2显著减少散射颗粒机理的探讨

本文认为在石墨电阻炉中,散射颗粒主要来自碳、钼及其化合物等杂质的污染,通入的CO_2能和高温中蒸发出来的夹杂在气氛中和熔体表面的碳、钼等固体微粒产生化学反应,生成挥发性的CO、MoO_2、Mo(CO)_6等气态物质而除去,大大减少了炉内材料对熔体的污染,从而减少了晶体的捕获对象,使晶体的散射颗粒显著减少。     

生长条件对KDP晶体中散射颗粒的影响

利用透射电子显微技术对不同条件下生长的KDP晶体中包裹物进行了观察并测量了其相应尺寸。结果表明，晶体中的生长缺陷、pH值、生长速度和杂质与KDP晶体散射颗粒的形态存在密切关系。     

Nd:YAG晶体中散射颗粒的研究(一)——Nd:YAG晶体散射及其对激光性能的影响

散射颗粒是Nd:YAG晶体中的一种缺陷,由散射颗粒所引起的散射损耗占光衰减的很大比重。我们通过对晶体散射颗粒的观察和对散射强度的测量证明了散射损耗严重影响激光的单程损耗、阈值、效率等激光性能。同时,对散射颗粒造成晶体的自身破坏     

压电晶体-固体-液体结构中IDT的体声波激励

对压电晶体－固体（层）－液体结构中叉指换能器的体声波激励效应进行了深入探讨，通过引入压电晶体－固体层界面的界面有效介电常数，研究了叉指换能器的体声波激励效应与晶体切向、电边界条件及固体层归一化厚度之间的关系。数值分析表明，电边界条件对叉指换能器体声波激励效应的影响可忽略；体声波激励效应与压电晶体切向和固体层归一化厚度密切相关；通过选择恰当的晶体切向、固体层归一化厚度和慢度，叉指换能器仅向液体中激励体声波，且可确定出最强体声波激励时的结构参数。文中所得结果，为有关液体声传感器结构的优化设计奠定了基础。     

Au纳米颗粒的形状和尺寸对表面等离子体的影响

通过调控Au纳米颗粒的形状和尺寸,研究了Au纳米颗粒的形状和尺寸与表面等离子体之间的关系。通过直流磁控溅射的方法在外延片上溅射Au薄膜,并采用快速热退火和常规热退火两种方式对其进行热退火,制备出Au纳米颗粒。使用不同热退火方式、不同热退火温度及不同Au薄膜厚度来改变Au纳米颗粒的形状和尺寸,并对Au纳米颗粒的表面形貌及它的消光谱进行了分析,对比了不同形貌的Au纳米颗粒对表面等离子体共振特性的影响。实验结果表明,使用普通热退火制备的Au纳米颗粒形状接近球体,而使用快速热退火得到的Au纳米颗粒的形状更接近棒体;随着热退火温度的升高,表面等离子体的共振波长发生红移;随着Au薄膜厚度的增加,表面等离子体的共振波长也发生红移。     

Nd:YAG晶体散射颗粒的研究(二)—Nd:YAG晶体中散射颗粒的观察与分析一

一、引言在前文中,阐明了散射颗粒对晶体激光性能的影响。实验证明:在YAG:Nd晶体中若存在散射颗粒则使激光内耗、振荡阈值明显增高、效率显著降低、破坏阈值下降。在散射颗粒很多的情况下甚至影响到晶体不     

室温和350℃下注Mn的GaAs／AIGaAs超晶格的磁学性质

通过室温和350℃注Mn后热退火，在GaAs／AlGaAs超晶格中引入了不同的亚微米磁性颗粒．利用原子力显微镜、能量散射X射线谱、X射线衍射和交变梯度磁强计研究了该颗粒膜材料的结构和磁学性质．通过比较这些颗粒的饱和磁化强度、剩余磁化强度、矫顽力和剩磁比，发现350℃注Mn的样品含有MnGa和MnAs两种磁性颗粒，而室温注Mn的样品主要含有MnAs颗粒．     

利用快速退火法控制非晶硅薄膜中纳米硅粒尺寸

报道了利用快速退火法控制膜中纳米硅粒大小的方法,讨论了升温快慢与所形成的纳米硅粒大小的关系.     

Effect of rapid thermal annealing on the current-voltage characteristics of 4H-SiC Schottky diodes

The effect of rapid thermal annealing (temperature 600–800°C; duration 2 min) on the forward current-voltage characteristics of 4H-SiC Schottky diodes is studied. Tungsten, nickel, chromium, and molybdenum deposited by electron-beam sputtering in vacuum are used as the Schottky-contact metals. Dissimilar types of influence exerted by the thermal treatment on the barrier height and scatter of the contact parameters, which characterize the degree of their uniformity, are found for different metals.     

热处理升温快慢对非晶硅中形成的纳米硅粒尺寸的影响

含氢非晶硅薄膜经过快速热退火处理后,我们用拉曼散射和X-射线衍射技术对样品进行分析.我们的实验结果表明:在非晶硅薄膜中形成的纳米硅晶粒的大小随着热退火过程中升温快慢而变化.在升温过程中,当单位时间内温度变化量较大时（～100℃/s）,则所形成纳米硅粒较小（～1.6～15nm）;若单位时间内温度变化量较低（～1℃/s）,则纳米硅粒较大（～23～46nm）。根据分形生长理论和计算机模拟,我们讨论了升温快慢与所形成的纳米硅颗粒大小的关系.     

热处理过程对HgCdTe光伏探测器性能的影响

本文论述了HgCdTe光伏探测器的I-V特性和暗电流机制,讨论了离子注入后退火、钝化后烘烤、倒焊互联后退火等热处理过程对HgCdTe光伏探测器性能的影响。     

Electrical resistivity of thin electroless Ag–W films for metallization

It is shown that optimization of the electroless deposition and the use of vacuum annealing yield dramatic decrease in the resistivity and its scatter in 100- and 50-nm silver–tungsten (Ag–W) films. Physical processes, which control the resistivity drop during low-temperature annealing and the residue resistivity in the annealed films are discussed.     

a-SiH 热处理过程中纳米硅粒尺寸的控制(英文)

报道了控制热处理过程中含氢非晶硅中纳米硅颗粒大小的一种新方法。用喇曼散射、X射线衍射和计算机模拟,发现在非晶硅中所形成的纳米硅颗粒的大小,随着热退火过程中升温速率的变化而变化。在退火过程中,若非晶硅薄膜升温速率较高(～100℃/s),则所形成纳米硅粒的大小在1.6～15nm;若非晶硅薄膜升温速率较低(～1℃/s),则纳米硅粒大小在23～46nm。根据晶体生长理论,讨论了升温速率的高低与所形成的纳米硅颗粒大小的关系。     

Characteristics of gallium arsenide structures and Gunn devices based on them fabricated using the radiation-thermal technology

Doped layers were produced by implanting sulphur ions into single-crystal GaAs and also into GaAs epitaxial films grown on semi-insulating substrates, with subsequent thermal annealing. An additional radiation treatment was performed using halogen lamps (photon annealing). Gunn devices and integrated circuits based on them were fabricated by planar technology. The additional treatment was shown to lead to an increase in the electron mobility in the layers due to the reduction of the concentration of scattering center. The Gunn-device structures, which were subjected to photon annealing, are characterized by better homogeneity and higher values of the current drop. Nearly ideal current pulses were generated in such structures, and no effects caused by trapping, as well as by the impact ionization, were observed.     

Degradation and recovery of AlGaAs/GaAs p-HEMT irradiated by high-energy particle

Results of an extensive study on the irradiation damage and its recovery behavior resulting from thermal annealing in AlGaAs/GaAs pseudomorphic high electron mobility transistors (HEMTs) subjected to a 220-MeV carbon, 1-MeV electrons and 1-MeV fast neutrons are presented. The drain current and effective mobility decrease after irradiation, while the threshold voltage increases in positive direction. The decrease of the drain current and mobility is thought to be due to the scattering of channel electrons with the induced lattice defects and also to the decrease of the electron density in the two dimensional electron gas region. Isochronal thermal annealing shows that the device performance degraded by the irradiation recovers. The decreased drain current for output characteristics recovers by 75% of pre-rad value after 300°C thermal annealing for AlGaAs HEMTs irradiated by carbon particles with a fluence of 1×10¹² cm⁻². The influence of the materials and radiation source on the degradation is also discussed with respect to the nonionizing energy loss. Those are mainly attributed to the difference of particle mass and the probability of nuclear collision for the formation of lattice defect in Si-doped AlGaAs donor layer. A comparison is also made with results obtained on irradiated InGaP/InGaAs p-HEMTs in order to investigate the effect of the constituent atom. The damage coefficient of AlGaAs HEMTs is also about one order greater than that of InGaP HEMTs for the same radiation source. The materials and radiation source dependence of performance degradation is mainly thought to be attributed to the difference of mass and the possibility of nuclear collision for the formation of lattice defects in Si-doped donor layer.     

硅/硅直接键合的界面应力

硅/硅直接键合技术广泛应用于SOI,MEMS和电力电子器件等领域,键合应力对键合的成功和器件的性能产生很大的影响。键合过程引入的应力主要是室温下两硅片面贴合时表面的起伏引起的弹性应力;高温退火阶段由于两个硅片的热膨胀系数不同引起的热应力和由于界面的本征氧化层或与二氧化硅键合时二氧化硅发生粘滞流动引起的粘滞应力。另外,键合界面的气泡、微粒和带图形的硅片键合都会引入附加的应力。     

退火对非晶态碲镉汞薄膜稳定态光电导的影响

利用射频磁控溅射方法,在宝石衬底上制备了非晶态碲镉汞(a-HgCdTe)薄膜。对原生a-HgCdTe薄膜进行了不同退火时间和不同退火温度的热退火,在80～300K温度范围内,分别测量了原生和退火处理后的a-HgCdTe薄膜样品的稳定态光电导,研究了退火时间和退火温度对非晶态HgCdTe薄膜的稳定态光电导和激活能的影响。结果表明,原生和退火a-HgCdTe薄膜的稳定态光电导具有热激活特性;随着退火时间增加或退火温度升高,a-HgCdTe薄膜的晶化程度提高,导致光电导增大,光电导激活能降低。利用非晶-多晶转变机制讨论了实验结果。