SACP技术在红外器件研制工艺中的应用探讨

各类半导体器件的性能几乎都与界面状态有关,研制高性能的红外探测元件首要的就是如何获得表面无污染、无损伤、结构完整的优质晶片。诚然,晶体结构的完整性取决於晶体生长,而晶片表面的污染,损伤则与晶片制作的各种工艺密切相关。本文介绍利用电子通道技术来检验半导体晶片表面的污染、损伤及结构完整性我们所进行的一些初步工作。对由同一晶锭上切割下的碲镉汞晶片任取10片分为两组进行了对比分析。结果表明在机械磨、拋     

立方晶体的理想电子通道图及其快速注释方法

采用晶面的极射赤面投影方法,从理论上绘制了一套不同立方晶体的理想电子通道图,为了迅速注释从实验所得的立方晶体的电子通道花样,用上述理想电子通道图的数据制成图表,可以大大节约注释时间。误差分析表明,本注释方法不但适用于晶带轴平行于扫描电镜的光轴情况,而且适用于晶带轴倾斜于光轴的情况。     

晶格热振动对磁场中半无限极性晶体内表面磁极化子自陷能的影响

采用Huybrechts的线性组合算符法和变分法 ,研究了晶格热振动对磁场中半无限极性晶体内电子与表面光学 (SO)声子强耦合、与体纵光学 (LO)声子弱耦合体系的影响 ,得到了作为距离晶体表面的深度、磁场和温度函数的表面磁极化子的自陷能 .对AgCl晶体进行了数值计算 ,结果表明 ,不同支声子与电子相互作用对表面磁极化子自陷能的贡献以及它们随距离晶体表面的深度、磁场和温度变化的情况大不相同 .     

高倍多晶电子通道显微像的观察与应用

本文观察研究了多晶银高倍电子通道显微像,并用银的标准电子通道图对晶粒位向与色调关系作了解释,提出了利用电子通道显微像确定晶粒位向的方法。还利用电子通道显微像观察到银表面的结晶膜。     

高效可见光发射多孔硅的红外光致发光表征

研究了７７Ｋ下高效可见光发射多也硅材料的红外光致发光光谱，并对多孔硅表面的硅晶体完整性作了分析和表征。     

声子之间相互作用对表面磁极化子有效质量的影响

本文研究极性晶体中电子与表面光学（ＳＯ）声子耦合器，与体纵光学（ＬＯ）声子耦合弱的表面磁极化子的性质，采用线性组合算符和微扰法导出了极性晶体中表面磁极化子的有效哈密顿量。讨论了电子在反冲效应中发射和吸收不同波矢的声子之间相互作用对表面磁极化子有效质量的影响。     

硒化锌晶体超精密切削材料去除机理研究

硒化锌晶体在红外成像与激光系统中有着广泛的应用,作为典型软脆性材料,其材料去除机理目前尚不清晰,获得超光滑表面仍极具挑战。文中采用槽切法研究刀具负前角对硒化锌晶体脆塑转变临界深度的影响。通过分析最大未变形切削厚度随切削参数变化规律,提出实现硒化锌晶体塑性域切削的理论模型。借助场发射扫描电子显微镜、白光干涉仪和拉曼光谱仪,系统分析了进给率对工件表面粗糙度、表面完整性及亚表面损伤的影响,提出表面缺陷形成机理,进而揭示硒化锌晶体材料去除机理。     

声学形变势表面极化子中的平均声子数

利用线性组合算符方法，计算了声学形变势表面极化子中的平均声子数，结果表明，光学声子平均数（Na）和声学声子平均数（Nb）均是电子运动速度和电子距离晶体表面的深度的函数。对AgCl晶体进行数值计算，结果表明：Na和Nb均随深度Z的增加而减少；Na随振动频率λ的增加而选减后增；Nb随η的增加而减少；并且，对慢速运动的电子，电子运动速度对Na、Nb的影响可以忽略。     

X射线衍射形貌术在碲锌镉晶体中的应用

碲锌镉晶体中存在着各种典型晶体缺陷,X射线衍射形貌术是一种非破坏性地整体研究晶体材料结构完整性、均匀性的有效方法。本文将反射式X射线衍射形貌术应用于碲锌镉晶体质量的评价,研究了入射线狭缝宽度、积分时间、扫描步长等测试参数以及样品表面加工状态对X射线衍射形貌的影响。结果表明入射线狭缝宽度对碲锌镉晶体的X射线衍射成像及晶体质量筛选应用影响很大,积分时间、样品扫描步长等测试参数的选择与入射线狭缝宽度密切相关。     

阴极蒸发物电子发射现象的研究

为研究钡钨阴极蒸发物的电子发射现象,采用一种新设计的测试装置,对沉积在多晶钨表面上阴极蒸发物的电子发射曲线进行了采集,利用电子发射显微镜和扫描电镜对蒸发物沉积层的电子发射像、表面形貌和成分进行了分析。结果表明,电子发射曲线分3段,即陡升段、快升段和缓升段。分析认为,发射曲线的3段依次对应着多晶钨表面的晶界及划痕发射、晶面发射和3维岛状发射。实践证明,在覆膜阴极表面构造均匀弥散分布的岛状晶体发射点,可大幅度提高阴极的电子发射性能。     

Silicon-germanium alloy growth control and characterization

Silicon-germanium alloy has been grown on silicon substrates by the hydrogen reduction of silicon tetrachloride and germanium tetrachloride as well as the pyrolysis of silane and germane. The film growth characteristics in the first few minutes have been studied using an SEM. Techniques have been developed for growing high germanium content films which are single crystal and have surfaces suitable for MOS device fabrication.     

PDLC器件显示迟滞效应的改善

目前ＰＤＬＣ器件的制作方法有多种,但器件在显示时其电压一透过率特性通常存在明显的迟滞效应,不利于灰度显示。采用在ＰＤＬＣ基板内表面涂覆液晶取向层,使取向层沿非平行方向摩擦的方法可使迟滞效应得到显著改善。     

Liquid‐Crystal Composites Composed of Photopolymerized Self‐Assembled Fibers and Aligned Smectic Molecules

A new liquid‐crystal composite, composed of photopolymerizable self‐assembled fibers and a smectic liquid crystal, and its photopolymerized composite have been prepared. The fibers oriented along the smectic layers are obtained by self‐assembly of an amino acid derivative with terminal methacryloyl groups in the smectic liquid crystal. The oriented fibrous structures are fixed by photopolymerization, resulting in the formation of microgrooves on the substrate surfaces. The aligned direction of the liquid‐crystalline molecules is changed to the direction along the fibers after thermal annealing. The patterning of liquid‐crystal alignment is achieved for these liquid‐crystal composites by patterned photopolymerization.     

Fully Canonical Pseudo-Elliptic Bandpass Filters on Multilayer Liquid Crystal Polymer Technology

Microstrip pseudo-elliptic bandpass filters, operating in the X-band, have been designed and implemented on multilayer liquid crystal polymer (LCP) technology for the first time. Folded open loop resonators printed on different dielectric surfaces and sharing the same ground plane are coupled through slots etched in the ground plane. Fully canonical filtering and modularity have been achieved through introduction of internal nonresonant nodes. Multilayer configuration is realized through thermocompression bonding of thin sheets of LCP. The designed fourth-order filter exhibits a low insertion loss of 3.2 dB at 9.9 GHz     

Control of the crystalline phase and morphology of CdS deposited on microstructured surfaces by chemical bath deposition

Chemical bath deposition (CBD) has been used extensively to deposit thin films of CdS for window layers in solar cells. The microtopography or roughness of the surface, however, can affect the quality of the film by influencing the morphology, uniformity, or crystal phase of the CdS film. Here, we have demonstrated that thin films of CdS can be successfully patterned on surfaces bearing micropillars as a model surface for roughness. The phase purity of CdS deposited on the micropillar surfaces is uniform and conformal with the formation of packed clusters on the micropillars at pH 10 that form flower-like structures at long deposition times. Smaller crystallites were observed on micropillar arrays at pH 8 with “network” like structures observed at long deposition times. Additionally, by controlling the pH of the chemical bath, the hexagonal and cubic crystal phases of CdS were both accessible in high purity at temperatures as low as 85 °C.     

反射率对入射角扫描测定单轴晶体的折射率

通过分析波矢沿任意方向的单轴晶体的折射率,在光轴位于入射面内时,给出了入射光分别为s光和p光的反射率拟合函数。利用改进的反射率扫描仪,测量了CaCO3晶体的s光和p光反射率随入射角变化情况,由理论拟合获得单轴晶体的两个主折射率,分别为no=1.6559和ne=1.4851。这种方法不需要对样品进行加工,其精度达到0.0001。另外,对于晶体光轴未知的情况,采用改进的布儒斯特技术分别测出三个晶体表面的布儒斯特角,由此可以确定光轴的方向。     

Influence of Hydrogenation on Electrical Conduction in HgCdTe Thin Films on Silicon

HgCdTe is the standard state-of-the-art infrared detector material for space applications. HgCdTe-based infrared photon detector performance can be hindered due to the presence of bulk crystal defects and dangling bonds at surfaces or interfaces. Passivation of such bulk defects and surfaces can potentially improve detector performance by saturating dangling bonds in dislocation cores and at surfaces. Indeed, results showing improvement of HgCdTe current–voltage characteristics after hydrogenation have been reported. Here we use multiple-carrier fitting of Hall-effect data, acquired under variable magnetic field strengths and sample temperatures, to investigate the physical influence of hydrogenation, as a passivation procedure, on HgCdTe crystalline thin films on Si(211) substrates. We find: (1) evidence of multiple active electrical carrier species in all samples, (2) evidence of surface electrical conduction before and after hydrogenation, and (3) changes in carrier concentration and mobility induced by hydrogenation.     

Cleaning method of InSb [111] B of n-InSb [111] A/B for the growth of epitaxial layers by liquid phase epitaxy

The crystal structure of InSb[111]A/B surfaces shows that this structure is polarized.This means that the surfaces of InSb[111]A and InSb[111]B contain two different crystallized directions and they have different physical and chemical properties.Experiments were carried out on the InSb[111]A/B surfaces,showing that tartaric acid etchant could create a very smooth surface on the InSb[111]B without any traces of oxides and etch pit but simultaneously create etch pit on InSb[111]A surfaces.After lapping and polishing,some particles remained on the InSb[111]B surface,they could not be removed easily by standard cleaning process and if these particles remain on the surface of the substrate,the growth layer was not uniform and some island-like regions were observed.The purpose of this work is to remove these particles on the InSb[111]B surface.Some morphology images of both surfaces,InSb[111]A/B,will be presented.     

碲锌镉晶体的范性形变研究

从经典的晶体范体形变的理论模型和面心立方闪锌矿结构晶体所具有的滑移特性出发，对碲锌镉晶体经特定化学试剂侵蚀后在（１１１）和（１－↑１－↑１－↑）面上出现的不同形貌蚀坑的形成机理进行了探讨，提出了碲锌镉晶体中存在多系滑移，从而阐明了不同极性面上蚀坑的成因。     

Comparison of the homoepitaxial growth of AlN crystals on Al and N surfaces

A special experimental technique capable of excluding the influence of differences between sources, substrate crystals, and growth process parameters has been employed to correctly compare the quality of homoepitaxial AlN layers grown by sublimation on Al and N surfaces of the substrate crystal with 〈0001〉 orientation. It has been found that, in most cases, the quality of layers grown on the N surface is somewhat higher; however, no differences have been observed in separate cases. Hence the conclusion follows that the range of growth process parameters is substantially wider for the N side compared with the Al side.