CdZnTe晶体表面Au电极薄膜的制备及其欧姆接触性质

为了研究不同制备工艺对电极欧姆接触特性的影响, 分别采用真空蒸发法、溅射法及化学沉积法在CdZnTe晶片表面制备了Au薄膜电极, 通过测试样品的SEM、I-V曲线及交流阻抗谱, 研究了不同电极制备工艺及退火处理对Au薄膜电极的微观结构及欧姆接触特性的影响。结果表明化学沉积法制备的Au薄膜表面更加平整、致密, 接触势垒的高度较低, 电极欧姆接触特性最好。退火处理可以改善电极的欧姆接触特性, 100℃退火后, 化学沉积法制备的Au电极的欧姆系数由0.883提高至0.915, 势垒高度由0.492降低至0.487 eV。交流阻抗谱分析表明, 化学沉积法制备电极具有最低的接触势垒, 这与界面处晶片表面的掺杂及缺陷的变化有关。     

M/HgI2接触特性分析

利用不同的电极材料和制备方法制备了3种M/HgI2。采用热电子发射模型计算了相应的接触势垒。采用比接触电阻法、电极系数法和欧姆系数法对比了M/HgI2的欧姆接触特性。结果表明,C/HgI2、AuCl3/HgI2和Au/HgI2的接触势垒均约为0.9eV;C/HgI2和AuCl3/HgI2具有良好的欧姆特性,Au/HgI2的欧姆特性相对较差。分析认为,HgI2晶体表面费米能级的钉扎导致了相近的接触势垒。但由于电极制备工艺没有显著影响AuCl3/HgI2和C/HgI2晶体表面质量,因而具有良好的欧姆接触特性。由于溅射Au电极在制备工艺中的温度升高和真空度造成Au/HgI2晶体表面质量下降,因此其欧姆接触特性较差。     

Au-CZT与Au/Cr-CZT接触性能比较

本文通过附着力测试,应力模拟和IV特性及多道能谱分析对Au-CZT与Au/Cr-CZT接触进行研究。结果表明采用Au/Cr复合电极可提高电极附着强度和热稳定性。在老化实验中,Au-CZT界面附着力下降了61.98%,而Au/Cr-CZT仅降低28%。Au/Cr电极器件的漏电流较低,241Am射线下能谱响应更佳。分析其原因可能是Au与CZT间的Cr层降低了接触层内的热应力,合金化过程促进了金-半界面的互扩散,使Au和CZT更易形成欧姆接触,综合考虑Au/Cr复合电极能获得比Au电极更理想的接触性能。     

Au/p-CdZnTe欧姆接触的电学测量及界面特性分析

采用化学镀金法在高阻p-CZT(CdZnTe)晶片表面制备Au电极,并用改进的圆环传输线模型(Ring-CTLM)测量了CZT电极的接触电阻,探讨了大气气氛下退火温度对CZT电极欧姆特性的影响.实验结果表明,200℃退火可以显著改善欧姆特性,使接触电阻率ρc显著减小,采用Ring-CTLM模型测得CZT与金电极接触电阻率为0.1524Ω·cm2.通过XPS分析了CZT与Au电极接触界面的成分,发现在Au/p-CdZnTe界面处形成了CdTeO3层,该界面层可起到载流子复合中心的作用,构建的新模型很好地解释了化学镀金法在p-CdZnTe晶片表面形成欧姆接触的机理.     

溅射膜电极与氧化锌压敏陶瓷的界面机制研究

利用溅射法制备半导体陶瓷表面的电极有着广阔的产业化前景,但关于溅射膜电极与陶瓷表面的界面机制研究尚鲜有报道。本文采用磁控溅射法在ZnO压敏陶瓷表面制备了Cr+Cu电极,通过X射线光电子能谱等技术研究分析了Cr/ZnO的界面反应及界面成分。研究结果表明:常温下Cr膜在氧化锌表面的沉积模式为混态生长模式,在Cr的初始沉积阶段,Cr价层电子与氧化锌表面存在电子转移作用,有氧化态的Cr生成;随着覆盖度的增加,电子转移逐渐减弱,最后Cr完全呈现为金属态的中性吸附。该界面反应生成的化合物对溅射膜电极的欧姆接触,附着力等性能有重要作用,而且能有效阻止电极元素Cu或Ag的纵向扩散。     

复合背接触层与背电极的匹配对CdTe太阳电池性能的影响

本文研究Ni和Au两种背电极在有、无ZnTe/ZnTeCu背接触层时对碲化镉太阳电池性能的影响及其机理.试验结果表明,在没有ZnTe/ZrTeCu复合背接触层时,Ni和Au相比,输入特性的填充因子(FF)较差,短路电流密度(Jsc)较大,转换效率(η)较低;在有zrTe复合背接触层时,Ni和Au相比,FF相差较小,而η因Jsc较大而较高.通过暗特性的测试,可以看到,在有了ZnTe复合背接触层以后,Ni作背电极的碲化镉太阳电池,其二极管因子(A)、暗饱和电流(Jo)和旁路电阻(Rsh)等三个参数降低的幅度都比Au作背电极的大.这和ZnTe复合背接触层使Ni背电极碲化镉太阳电池效率有更大提高是吻合的.分析表明,这主要是由于光生电流的增大导致了Jsc的增大.这样用Ni代替Au作背电极会带来降低成本和效率提高的双重改进.     

直流磁控溅射BaTiO3系PTCR元件电极及其性能对比的研究

目前在钛酸钡系PTC热敏电阻器的生产过程中,广泛采用烧渗铝、化学镀镍等电极制备方法,但所制备的电极湿热老化及附着力不尽人意.本文采用直流磁控溅射法制备了的PTCR元件的底电极,实现了镍与PTCR瓷片间的欧姆接触,并发现利用溅射法工艺制备了Ni电极的元件电极附着力(垂直拉力＞3kg,剪切拉力＞0.5kg)及耐湿热老化性能均得到提高,而且溅射工艺的高成本也得到控制,在生产上实现了批量应用(日产量可达3万片).     

1-3型压电复合材料电极的制备

采用磁控溅射工艺以Cu、Ag为靶材在1-3型压电复合材料表面制备电极．研究了两种金属材料的溅射镀膜工艺，系统地分析了溅射功率对金属沉积速率、电极导电性能及附着力的影响．结果表明，两种金属的沉积速率随溅射功率的增加呈线性增加，电极方阻及电阻率均随功率增大而减小，溅射功率为100W时电极的附着力较好．     

磁控溅射法制备电磁屏蔽织物的研究

本文采用直流磁控溅射在无纺布基底上溅射沉积金属铜来制备电磁屏蔽织物。通过原子力显微镜观察发现,工艺参数对溅射沉积速率以及膜层的表面形貌都有较大的影响。在一定范围内,溅射功率越大,沉积速率越大,膜层颗粒分布越均匀致密。溅射压力一般选取0.9 Pa左右为宜,在此压力下,溅射沉积速率最大。经测试膜层与基底结合牢度较好,溅射沉积铜后透气性变化较小。频谱分析仪测试结果表明织物的屏蔽性能十分优良。     

Si基有机光电探测器低阻欧姆电极制作

在Si单晶表面真空沉积有机半导体材料苝四甲酸二酐(PTCDA)可形成有机/无机异质结。利用铟锡氧化物(ITO)沉积在PTCD表面作为光的入射窗口,在其表面溅射Al/Ni接触电极,在氢气保护气氛中经350℃,3分钟合金化,其比接触电阻ρs达5.2×10-5.cm2。利用α台阶仪,原子力显微镜,紫外可见分光光度计及x射线衍射仪,对其形成良好低阻欧姆电极的工艺条件及表面和界面进行了分析讨论。     

Effects of low-temperature annealing on Ohmic contact of Au/p-CdZnTe

Effect of annealing time at 333 K in air on the ohmic property of Au/p-CdZnTe contact was studied. Through I–V measurement, it was found that Au/p-CdZnTe had excellent ohmic property after 2 h annealing. SEM and XPS analyses showed that Au atoms diffused into CdZnTe during annealing. Diffused Au did not form any compound with any element in CdZnTe, but replaced Cd sites or occupied Cd vacancy as acceptors. Thus, the heavy p-type doping layer was formed and M-p⁺-p ohmic contact was obtained. At the same time, about 27.01% of Te in un-deposited CdZnTe surface layer was oxided into TeO₂ during 2 h annealing.     

Effects of contact interface degradation on the performance of CdZnTe detectors

The characteristics of the Au contacts deposited by three different processes before and after accelerating aging tests have been investigated in this paper. The experimental results indicate that the aging tests can cause the degradation of the contact interfacial properties, such as continuities, adhesion strength and ohmic characteristics, especially for the contact electrode deposited by the thermal vacuum evaporation, which would influence the performance of CdZnTe detectors.     

P型高阻CdZnTe晶体表面接触的电学性能研究

用原子力显微镜（ＡＦＭ）研究了Ｐ型高阻Ｃｄ０．８Ｚｎ０．２Ｔｅ晶体表面状况对接触电学特性的影响,研究了三种金属和ＡｕＣｌ３作为接触层材料的电学特性和接触机理。研究表明采用化学方法沉积ＡｕＣｌ３膜能在ＣｄＺｎＴｅ光滑表面形成一层重掺杂层,较金属更易获得欧姆接触,热处理可改善接触的欧姆性,增强接触层与晶体表面的结合力。     

Nb-Ti/Al/Ni/Au based ohmic contacts to AlGaN/GaN

In this paper, we report on a novel Nb-Ti/Al/Ni/Au metallic system proposed to form ohmic contact to AlGaN/GaN heterostructure. The metallic system uses deposition of thin niobium layer as the first layer in contact with the AlGaN barrier layer before deposition of the conventional Ti/Al/Ni/Au metallic system. The fabrication and electrical characterization of the Nb-Ti/Al/Ni/Au based ohmic contacts are presented. We have shown that Nb-based ohmic contacts at optimal alloying temperatures seem to be superior to that of conventional Ti/Al/Ni/Au in both surface morphology and contact resistivity evaluation. Auger Electron Spectroscopy (AES) and Secondary Ion Mass Spectroscopy (SIMS) are also used to evaluate the improved ohmic contact formation.     

2.19 Conduction phenomena in NbNb2O5Au thin film structures fabricated by various techniques

Conduction mechanisms have been studied in niobium-niobium oxide-gold thin film sandwich structures with the oxide prepared by anodic oxidation and reactive sputtering, respectively. Different I–V characteristics have been obtained with diodes having gold electrodes made by both evaporation and sputtering. Significant rectification was found only, when evaporation techniques were used. For this type of diode the NbNb₂O₅ interface is generally assumed to act as ohmic contact, whereas the Nb₂O₅Au interface behaves like a Schottky contact. Conduction mechanisms relevant to the various portions of the I–V characteristics are discussed. Current drifts are also treated, which are attributed to the migration of ionized traps. A theoretical model explaining the drift phenomena is presented.     

Effect of thermal annealing on Ni/Au contact to a-InGaZnO films deposited by dc sputtering

We deposited Ni (15 nm)/Au (30 nm) layers on a-InGaZnO in order to produce low-resistance ohmic contacts by using a dc sputtering method. The samples were annealed at various temperatures for 5 min in Ar ambient. The electrical and the structural properties of the Ni/Au contact to a-InGaZnO were investigated. According to the current-voltage measurements, both the as-deposited and low-temperature annealed samples showed an ohmic behavior. The specific contact resistance of the as-deposited sample was 4.1 × 10^− 5 Ω cm², which was the lowest value. Further increasing the temperature above 400 °C led to an increase in the specific contact resistance. This is due to the chemical intermixing and formation of the oxide in the contact interface caused by the post-growth thermal annealing.     

硅基体表面无钯活化化学镀镍工艺

硅材化学镀镍的活化是为了获取金属原子沉积中心,但现有的活化工艺存在种种不足。金纳米粒子具有小尺寸效应、表面与界面效应,呈现出良好的催化活性。采用金纳米粒子对硅基体进行活化后化学镀镍,并采用浸泡腐蚀试验,SEM及EDS测试将其与传统的钯活化法对比,研究了活化后的沉积速度及镀层形貌、结构、耐腐蚀性能,结果表明：金纳米粒子活...