中波和长波红外碲镉汞光伏二极管的性能

HgCdTe的新型钝化剂 HgCdTe钝化剂的研究是普遍引人注目的课题。业已发现,HgCdTe自然氧化物钝化剂对辐射效应敏感。从传统习惯说来,表面钝化是把二极管性能达到所希望的理论值的一个决定性因素。已证明HgCdTe合适的钝化特别困难,这是因为这种合金的复杂性以及汞蒸汽压所决定的。自然氧化物的化学性质复杂,不适合将p型转变为n~+的过程,因为它能明显地转换成p型材料。而广泛使用的ZnS钝化剂能制备具有优良特性的二极管,但是,它     

p-CZT的钝化处理和C-V特性研究

采用NH4F/H2O2作为p-CZT晶片的表面钝化剂,对未钝化与钝化表面处理的p-CZT晶片的C-V特性进行了对比研究.用XPS分析了钝化前后CZT晶体表面成分,发现钝化后CZT晶片表面形成厚度为3.1 nm的TeO2氧化层.用Agilent 4294A高精度阻抗分析仪,在1 MHz下对未钝化的和钝化的CZT晶片进行C-V测试.对测试结果的计算表明,钝化提高了Au与CZT接触的势垒高度(∮)b.未钝化的(∮)b为1.393 V,钝化后(∮)b变为1.512 V.     

钝化剂自组装单层膜在铜铜键合工艺中的应用

解决铜铜键合工艺中的铜氧化问题对于三维集成技术具有重要意义。选用1-己硫醇做临时钝化剂,通过自组装形式形成单层膜附着于铜表面,以防止铜在存放时与空气接触而发生氧化,键合前再使用乙醇等有机溶剂去除该单层膜。为了评估1-己硫醇的钝化效果,采用接触角作为主要指标对实验结果进行评价。研究表明,样片表面经过1-己硫醇处理后,接触角极大增加,并在空气中长时间保持稳定,说明1-己硫醇具有良好的钝化效果,采用此方法得到了高质量的铜铜热压键合样片。     

绝缘体与Hg_(1-x)Cd_xTe界面特性

(Hg,Cd)Te光电器件的表面钝化工艺,特别是俘获电荷密度必须小于10~(11)cm~(-2)的长波光电二极管的有效钝化工艺,已探索了很长时间。这里存在两个难题:一是该材料对物理、化学处理的灵敏度问题,这将导致(Hg,Cd)Te表面化学配比发生变化和引起机械损伤;另一问题是它的热稳定性,这迫使我们进行低温钝化。很多资料证明,阳极化处理引起不能接受的高的固定电荷密度(～10~(12)cm~(-2)),这可能与半导体界面处发现的损伤层有关。本文简要介绍了这种或其他种类钝化剂的性质。     

铁基电镀锌层的无铬钝化处理研究

研究了镀锌板无铬钝化工艺技术,用以取代传统的高毒性铬酸盐钝化处理.以钼酸盐为主要成分,对镀锌钢板钝化工艺技术进行了系统的研究.讨论了钝化温度、钝化处理时间、钝化液pH值等对钝化成膜及膜层耐蚀性的影响.通过醋酸铅点滴试验,电化学测试等方法对无铬钝化样品的耐蚀性进行了研究.实验结果表明,该无铬钝化膜具有较好的耐腐蚀性,但与...     

镀锌层的军绿色钝化

军绿色钝化又称草绿色钝化或五酸钝化,是镀锌层的后处理方法之一。这种钝化膜外观从军绿色到灰绿色,宛如涂漆层。军绿色钝化膜外观典雅,光度柔和,钝化膜厚而致密,抗腐蚀性超过其他颜色的铬酸盐钝化膜。近几年来,这种钝化工艺己在许多产品上广为应用,除用于军品外,还用于纺织机械零件、汽车零件、标准紧固件和办公用品等。此外,由于军绿色钝化膜与油漆的结合力要比其他颜色的钝化膜大得多,因此,它还可作为油漆的底层而加以应用。     

长波光导HgCdTe探测器芯片钝化研究

在长波光导碲镉汞器件研制过程中，表面钝化是不可缺少的一个重要环节。在早期，表面钝化只进行阳极氧化处理。通过阳极氧化加ＺｎＳ复合钝化实验，得到了比较可靠的表面钝化层，并制造出了高性能、耐高温环境试验的实用化擦探测器芯片，文章对表面钝化层进行了分析。     

锡后处理对锡镀层性能的影响

分别测试了纯锡镀层经钝化及金属保护剂处理后的孔隙率、防变色能力、可焊、回流焊性能及抑制锡须生长情况。试验结果表明:对纯锡层采用钝化和金属保护剂处理均能有效降低镀层的孔隙率,提高镀层的防变色能力。金属保护剂处理能有效防止锡层的氧化,延长产品的储存寿命,对焊接性能无影响,同时能有效抑制锡须生长;钝化处理降低了锡镀层的焊接性能,对抑制锡须生长作用不明显。     

HgCdTe红外探测器CdTe钝化蒸发生长改进

在液相外延生长(LPE)的碲镉汞(HgCdTe)外延薄膜(111)方向上蒸发生长碲化镉(CdTe)钝化层。在70～250℃范围内的各个不同的温度环境下进行碲化镉钝化膜的蒸发生长。根据需要,对各样本进行150～300℃各个温度下的后期退火处理。运用扫描电镜(SEM)、透射电镜(TEM)、二次离子质谱(SIMS)、X射线衍射(XRD)观测技术表征碲化镉钝化膜的形貌结构、成分分布、晶体质量。结果表明,加热环境下蒸发生长碲化镉钝化膜可以消除常规蒸发生长中的柱状多晶结构,显著提高钝化品质;后期的退火处理还能进一步提高钝化膜质量。     

制备及钝化条件对多孔硅发光性能的影响

研究了氧化电流密度对多孔硅（PS）PL谱的影响。结果表明，随着氧化电流密度增大，PS的微晶Si平均尺寸减小，且尺寸的微晶Si数量也减少，说明制备条件对钝化PS的发光有影响；PS经适当的高温氧化处理后，其PL谱会发生明显变化；选用含有胺基的正丁胺，采用射频辉光放电法对PS进行钝化处理，在一定程度上提高了PS的发射强度伴随发光峰值的较大蓝移；其钝化PS的荧光谱随钝化温度和钝化时间变化，说明钝化条件对钝化PS的发光有直接影响。由此，可以通过调节制备和钝化条件来获得最大的发光效率和所需要的发光颜色。     

Passivation of HgCdTe p-n diode junction by compositionally graded HgCdTe formed by annealing in a Cd/Hg atmosphere

Cadmium telluride (CdTe) is being widely used for passivating the HgCdTe p-n diode junction. Instead of CdTe, we tried a compositionally graded HgCdTe as a passivation layer that was formed by annealing an HgCdTe p-n junction in a Cd/Hg atmosphere. During annealing, Cd diffuses into HgCdTe from the Cd vapor, while Hg diffuses out from HgCdTe, forming compositionally graded HgCdTe at the surface. The Cd mole fraction at the surface was constant regardless of the annealing temperature in the range of 250–350°C. Capacitance versus voltage (C-V) curves for p-type HgCdTe that were passivated with compositionally graded HgCdTe formed by Cd/Hg annealing at 260°C showed a smaller flat-band voltage than the one passivated by thermally deposited CdTe, indicative of the better quality of the passivation. A long-wave infrared (LWIR) HgCdTe p-n junction diode passivated by compositionally graded HgCdTe showed about a one order of magnitude smaller R_dA value than the one passivated by thermally deposited CdTe, confirming the effectiveness of the compositionally graded HgCdTe as a passivant.     

多晶硅太阳电池的氮化硅钝化

全面介绍了等离子增强化学汽相沉积 ( PECVD)纳米氮化硅 ( Si Nx∶ H)光电薄膜的技术发展及现状 ,分析了 PECVD法沉积的 Si Nx∶ H薄膜对多晶硅太阳电池的体钝化和表面钝化机理     

Topographic Evaluation of the Effect of Passivation in Improving the Performance of CdZnTe Detectors

Surface passivation reportedly is an effective technique for controlling surface leakage current and its related electronic noise. Several chemical agents have been effectively used for passivating cadmium zinc telluride (CdZnTe or CZT) surfaces; however, the long-term stability and the adverse effect on the metal contacts remain questionable. In this study, we reviewed two popular passivating agents, viz. hydrogen peroxide (H₂O₂) and a mixture of ammonium fluoride and hydrogen peroxide (NH₄F + H₂O₂). Our aim was to identify an ideal one that can effectively and permanently lower surface leakage currents without adversely affecting the metal contacts. We characterized their topographic features and their long-term effectiveness in terms of detector performance, and compared the results to understand their nature. We determined which chemical species were formed, and recorded the peaks of elemental Cd and Te via x-ray photoelectron spectroscopy (XPS) and micron-scale spatial resolution x-ray fluorescence (μ-XRF). We describe in detail the formation of new chemical species and the material nonuniformity of differently treated surfaces. Their effectiveness was assessed from experimental findings of their electrical properties and the spectral response. Our results imply that both passivating agents lowered the surface leakage current, and improved the detection efficiency of the CZT detectors, but their effectiveness was unstable over time.     

Reactive ion beam deposition of aluminum nitride thin films

Aluminum nitride thin films have been prepared at room temperature by reactive ion beam sputtering for potential use as a passivant and diffusion/anneal cap in compound semiconductor technology. The electrical and optical pro-perties of these films have been studied along with the in-fluence of thermal annealing on the material characteristics. The quality of the films has also been found to improve in the presence of atomic hydrogen during the deposition.     

Edge passivation and related electrical stability in silicon powerdevices

Factors governing long-term stability of silicon power devices are discussed with particular reference to a major failure mechanism observed in a thyristor device. The device failure was due to electrical instability during an electrical and thermal stability storage test, wherein it was observed that the reverse blocking voltage deteriorated under applied bias at the rated maximum junction temperature. The major cause of this failure was identified as lack of exhaust during the edge passivation and curing process due to which excessive chemical deposits are retained in the bevel region of the silicon element. This contributes to surface leakage current and, hence, a rapid degradation of the off-state characteristics. An orthogonal array experiment was employed to optimize the process factors and levels. The manufacturing process was then modified by incorporating an effective exhaust system in the passivant curing oven. This resulted in marked improvements in the electrical stability and manufacturing yield of this device     

Nitride chemical passivation of a GaAs (100) Surface: Effect on the electrical characteristics of Au/GaAs surface-barrier structures

The effect of chemical nitridation of GaAs substrates in a hydrazine-sulfide solution on the electrical characteristics of Au/GaAs Schottky structures has been studied. In nitridation of this kind, a solid passivating gallium nitride film with a monolayer thickness is formed on the surface of GaAs, providing almost direct contact between the semiconductor and the metal deposited on its surface. Au/GaAs structures fabricated on nitride substrates have ideality factors close to unity and are characterized by a narrow scatter of potential barrier heights. Prolonged heating of these structures at 350°C does not change these parameters. The data obtained show that the nitride monolayer formed on the GaAs surface upon treatment in hydrazidesulfide solutions effectively hinders atomic migration across the metal-semiconductor phase boundary.     

Surface Oxidative Characterization of LPE HgCdTe Epilayer Studied by X-ray Photoelectron Spectroscopy

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Surface passivation of cadmium zinc telluride radiation detectors by potassium hydroxide solution

The spectral resolution of cadmium zinc telluride (CZT) room temperature nuclear radiation detectors is often limited by the presence of conducting surface species that increase the surface leakage current. Surface passivation plays an important role in reducing this surface leakage current and thereby decreasing the noise of the detectors and improving the spectral energy resolution. Chemical etching with a Br-MeOH solution leaves CZT surfaces rich in Te and is considered as one of the primary causes of the increased surface leakage current. Previous studies have shown that hydrogen peroxide (H₂O₂) forms oxides of tellurium on the CZT surface and thus acts as a good passivating agent. In this study we will present results on the use of potassium hydroxide (KOH) as an alternative passivating agent. The KOH aqueous solution leaves a more stoichiometric (evaluated from the trends in the surface Cd:Te ratio) and smoother CZT surface. The passivation effects of KOH solution on the surface of the CZT have been characterized by current-voltage measurements for different KOH concentrations and etching times for both parallel strip electrodes as well as a metal-semiconductor-metal configuration. The surface chemical composition and its morphology were studied by scanning x-ray photoelectron spectroscopy and atomic force microscopy. The comparison and demonstration of improvements in the spectral resolution of the CZT detectors (based on ²⁴¹Am spectra) with and without the KOH treatment are presented.     

High-Performance Perovskite-Based Blue Light-Emitting Diodes with Operational Stability by Using Organic Ammonium Cations as Passivating Agents

Blue emissive perovskites can be prepared by incorporating chlorine into bromine-based perovskites to tune their bandgap. However, mixed-halide perovskites exhibit intrinsic phase instability, particularly under electrical potential, owing to halide migration. To achieve high-performance blue perovskite-based light-emitting diodes (PeLEDs) with operational stability, organic ammonium cations are used for passivating the anionic defects of the CsPbBr₂Cl film. Diphenylpropylammonium chloride (DPPACl), used as a passivating agent, successfully prevents the spectral instability of blue PeLEDs by passivating the Cl⁻ vacancies. Consequently, the blue PeLED prepared with this passivating agent delivers excellent device performance with a maximum external quantum efficiency of 3.03%. Moreover, upon tuning the DPPACl concentration, the PeLED emits stably in the deep-blue spectral region (464 nm) with a half-life time of 420 s. Thus, the use of organic ammonium cation as a passivating agent is an effective strategy for developing high-performance blue PeLEDs with operational stability.