Electromigration studies of flip chip Sn95/Sb5 solder bumps on Cr/Cr-Cu/Cu under-bump metallization

The electromigration-induced failure of Sn95/Sb5 flip chip solder bumps was investigated. The failure of the joints was found at the cathode/chip side after current stressing with a density of 1×10⁴ A/cm² at 150°C for 13 sec. The growth of intermetallic compounds (IMCs) was observed at the anode side after current stressing. Voids were found near the current crowding area in the cathode/chip side, and the (Cu,Ni)₆Sn₅ IMC at the cathode/chip end was transformed into the Sn phase. The failure mechanism for Sn95/Sb5 flip chip solder joint is proposed in this paper.     

In situ sulfurization to generate Sb2(Se1 − xSx)3 alloyed films and their application for photovoltaics

Because of its tunable band gap and band position, Sb₂(Se_{1 − x} S_x )₃ (0 ≤ x ≤ 1) is a promising light‐absorbing material for photovoltaic device applications. However, no systematic study on the synthesis and characterization of single‐phase polycrystalline Sb₂(Se_{1 − x} S_x )₃ thin films has been reported. Through introducing in situ sulfurization into the rapid thermal evaporation process, a series of single‐phase, highly crystalline Sb₂(Se_{1 − x} S_x )₃ films with x = 0.09, 0.20, 0.31, and 0.43 were successfully obtained, with the corresponding band gap, band position and film morphology fully revealed. Futhermore, solar cells with superstrate ITO/CdS/Sb₂(Se_{1 − x} S_x )₃/Au structure were fabricated and carefully optimized. Finally, a champion device having 5.79% solar conversion efficiency was obtained employing uniform Sb₂(Se_0.80S_0.20)₃ absorber layer. Our experimental investigation confirmed that Sb₂(Se_{1 − x} S_x )₃ is indeed a very promising absorber material worth further optimization. Copyright © 2016 John Wiley & Sons, Ltd.     

Preparation and characterization of glassy and superconducting (Bi,Pb, Sb)-Sr-Ca-Cu-O systems

Superconducting compounds with nominal compositions Bi_1.7Pb_0.3Sr_1.6Ca₂ Cu_3.4O _x and Bi_1.9Sb_0.1Sr₂Ca₂Cu₃O _y have been synthesized by ceramic and glass routes and characterized by X-ray diffraction, electrical resistivity and dielectric constant measurements. The zero-electrical resistance temperatures are about 70K. The dielectric constant of the glasses at room temperature is around 30.     

连续滴定法测定矿石及合金中砷锑含量

用浓硫酸溶样,在一定温度下,先用硫酸铈滴定,再用溴酸钾滴定,可分别计算出Sb和As的含量.该法操作简单、测定快速,相对标准偏差小于1.5%,适用于常规的矿石和合金中砷锑的测定.     

Sb掺杂Sn_2S_3薄膜的制备及光学特性

真空蒸发制备Sb掺杂Sn2S3多晶薄膜(玻璃衬底),研究不同比例Sb掺杂对Sn2S3薄膜的结构、表面形貌、化学组分及光学特性的影响。实验给出5%掺Sb的薄膜经380℃热处理30min(氮气保护)得到正交晶系的Sn2S3∶Sb多晶薄膜,薄膜表面颗粒大小均匀,膜面致密有轻微颗粒聚集现象。薄膜体内Sn与S化学计量比为1∶1.49,掺Sb后为1∶0.543,薄膜中Sn、S、Sb分别以Sn2+、Sn4+、S2-、Sb5+存在。纯Sn2S3薄膜的光透过率在350~500nm波长范围内基本为零,随着波长增大,光透过率增加,其直接光学带隙为2.2eV,吸收边为564nm;掺Sb后薄膜的光透率明显降低,光学带隙为1.395eV比未掺杂时减小0.805eV,吸收边发生红移为889nm。     

Highly Improved Sb2S3 Sensitized‐Inorganic–Organic Heterojunction Solar Cells and Quantification of Traps by Deep‐Level Transient Spectroscopy

The light‐harvesting Sb₂S₃ surface on mesoporous‐TiO₂ in inorganic–organic heterojunction solar cells is sulfurized with thioacetamide (TA). The photovoltaic performances are compared before and after TA treatment, and the state of the Sb₂S₃ is investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, and deep‐level transient spectroscopy (DLTS). Although there are no differences in crystallinity and composition, the TA‐treated solar cells exhibit significantly enhanced performance compared to pristine Sb₂S₃‐sensitized solar cells. From DLTS analysis, the performance enhancement is mainly attributed to the extinction of trap sites, which are present at a density of (2–5) × 10¹⁴ cm^?3 in Sb₂S₃, by TA treatment. Through such a simple treatment, the cell records an overall power conversion efficiency (PCE) of 7.5% through a metal mask under simulated illumination (AM 1.5G, 100 mW cm^–2) with a very high open circuit voltage of 711.0 mV. This PCE is, thus far, the highest reported for fully solid‐state chalcogenide‐sensitized solar cells.     

AIGaAsSb Buffer/Barrier on GaAs substrate for InAs channel devices with high electron mobility and practical reliability

InAs/AlGaAsSb deep quantum well was successfully formed on GaAs substrate and examined for two electron devices, Hall elements (HEs), and field-effect transistors (FETs). With a thin buffer layer of 600 nm AIGaAsSb on GaAs substrate, we observed high electron mobility more than 23000 cm²/Vs and extrinsic effective electron velocity of 2.2 x 10⁷ cm/s for a 15 nm thick InAs channel at room temperature. AIGaAsSb lattice matched to InAs was discussed from the view points of insulating property, carrier confinement, and oxidization rate. Reliability data good enough for practical use were also obtained for HEs. We demonstrated AIGaAsSb as a promising buffer/barrier layers for InAs channel devices on GaAs substrate, and we discussed the possible advantages of AIGaAsSb also for InGaAs FETs.     

Low-temperature processing of antimony-implanted silicon

It is shown for the first time that antimony-implanted silicon produces the highest electrical activation (90%) with low resistivity (<200 ohms/square) following low-temperature processing. Thus, annealing at 650°C produces the best results for antimony, whereas for arsenic, it is necessary to anneal at temperatures above 1000°C to get optimum results. Silicon was implanted with antimony at 12 keV and 40 keV and doses of 8.5×10¹⁴ cm⁻² and 4×10¹⁴ cm⁻², respectively, and arsenic at equivalent energies and doses. The electrical data from both implants are compared in order to identify the process conditions require to obtain optimum results. It is demonstrated that annealing below 800°C produces electrical profiles with no measurable diffusion of the antimony, but higher temperature anneals produce significant diffusional broadening.     

Radiation damage and annealing behaviour in Be+-implanted pure Ga(Al)Sb layers

Implantation of Be⁺ ions into GaAISb epilayers is used to realize thep ⁺ layer of the Ga_0.96Al_0.04Sb p⁺/Ga_0.96Al_0.04Sbn ⁻ /GaSbn ⁺ (1.55 /Μm) avalanche photodetector whose performances are detailed in Ref. (1). The GaAISb layers are grown using liquid phase epitaxy (LPE); the quality of these as-grown layers is shown through photoluminescence and channeling measurements. The last part of this paper is devoted to the damaging level in the Be⁺-implanted layers. Some annealing techniques are presented as a mean of restoration of the implanted layers. It is clear from the results that the Be⁺ ion implantation leads to a low damage level in this III-V compound.