Sn Contact Research Articles

Measurements of dichroic bow-tie antenna arrays with integrated cold-electron bolometers using YBCO oscillators.

We consider properties of dichroic antenna arrays on a silicon substrate with integrated cold-electron bolometers to detect radiation at frequencies of 210 and 240 GHz. This frequency range is widely used in cosmic microwave background experiments in space, balloon, and ground-based missions such as BICEP Array, LSPE, LiteBIRD, QUBIC, Simons Observatory, and AliCPT. As a direct radiation detector, we use cold-electron bolometers, which have high sensitivity and a wide operating frequency range, as well as immunity to spurious cosmic rays. Their other advantages are the compact size of the order of a few micrometers and the effect of direct electron cooling, which can improve sensitivity in typical closed-loop cycle 3He cryostats for space applications. We study a novel concept of cold-electron bolometers with two SIN tunnel junctions and one SN contact. The amplitude-frequency characteristics measured with YBCO Josephson Junction oscillators show narrow peaks at 205 GHz for the 210 GHz array and at 225 GHz for the 240 GHz array; the separation of these two frequency bands is clearly visible. The noise equivalent power level at an operating point in the current bias mode is 5 × 10-16 W/√Hz.

Optimization of the Cold-Electron Bolometer and a Quasiparticle Cascade Amplifier in the Voltage-Biased Mode

An optimized concept of the Cold-Electron Bolometer (CEB) with Superconductor-Insulator-Normal (SIN) Tunnel Junction and Andreev SN contact for voltage-bias mode has been developed. The responsivity of this design is much better than the widespread concept of the CEB with two SIN tunnel junctions for the current-biased mode (SINIS structure) due to degradation of responsivity by a factor of two in voltage-bias (VB) mode. Besides that, for the realization of the CEB with the same capacitance, we need twice larger junctions that lead to four times larger area and volume of the absorber. As a result, the NEP of one SIN junction CEB is half that of two SIN junction CEB. A novel concept of the quasiparticle cascade amplifier (QCA) based on harvesting the waste energy of relaxed quasiparticles without any additional voltage bias has been developed. The distinguish feature of the cascade principle is utilizing the same dc voltage as used for CEB. The cascade principle of signal amplification proved to be possible due to the conversion of electrons to holes in the second absorber. The amplifier is based on the optimized CEB with one SIN junction and one SN contact. The coefficient of power amplification of the incoming signal to the potential energy of hot quasiparticles is huge and can achieve a level of 140 at the optimal bias point. The coefficient of power amplification of the QCA can reach a value of 30 and more to overcome the noise of the SQUID amplifier. For a power load of 6 pW, the total NEP of the CEB is decreased to the level of photon noise NEP, down to 0.7*NEP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">phot</sub> .

High On-State Current in Chemical Vapor Deposited Monolayer MoS2nFETs With Sn Ohmic Contacts

Proving the device performance and process feasibility is imperative for the realization of two-dimensional (2D) semiconductor electronics. In this work, we have successfully adopted Tin (Sn) as the Ohmic contact metal to monolayer molybdenum disulfide (MoS2) grown by chemical vapor deposition (CVD) and demonstrated superior short channel n-type field effect transistor (nFET) performance reaching an ON-current of 480 μA/μm and keeping the OFF-current below 0.1 nA/μm at VDS = 1 V. These efforts are close to the low power specification of Si transistors in the metrics of International Roadmap for Devices and Systems (IRDS). The performance improvement could be attributed to the re-melting behavior of Sn metal. We suggest that the Sn deposited at lower temperatures could reduce the formation of interfacial defects caused by heat, and high-melting-point capping metal also could assist the re-melting phenomenon of underlying Sn contact layer. These process modifications are helpful to form smooth Sn coverage on MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , thereby reducing the contact resistance to 0.84 kQ · μm. This work provides a practical pathway to form low-resistance metal contact on 2D semiconductors for performance improvement.

Transesterification reactions of dimethoxycarbonylethyltin-pyrrolidinodithiocarbamate, [Sn(PDTC)2(CH2CH2COOCH3)2] – Spectroscopic and X-ray structural characterization of new estertin dithiocarbamate complexes – Part I

The reaction of [Cl2Sn(CH2CH2CO2Me)2] with sodium pyrrolidinodithiocarbamate (NaPDTC) in CHCl3 afforded [Sn(PDTC)2(CH2CH2CO2Me)2], (1). Transesterification reactions of (1) with different alcohols in the presence of dmso yielded [Sn(PDTC)2(CH2CH2CO2Et)2], (2), [Sn(PDTC)2(CH2CH2CO2Pr)2], (3), and [Sn(PDTC)2(CH2CH2CO2Bu)2], (4). All complexes were characterized by elemental analysis, FTIR, and 1H, 13C{1H} and 119Sn{1H} NMR spectroscopy. In addition, the crystal structures of (1), (2) and (4), determined by single-crystal X-ray diffraction, confirmed the presence of two different ester groups in each product, namely a free CO group and a CO⋯Sn chelating system. For (1), (2) and (4), the Sn-C bonds occupy the apical positions of a distorted pentagonal bipyramid, whereas the five equatorial positions are taken by the S donor centres of the unsymmetrically bonded dithiocarbamate ligands and the CO⋯Sn contact. Complexes (1) and (4) display 1D chain networks, while (2) exhibits a 2D supramolecular structure. The supramolecular networks in all complexes are held by intermolecular C-H⋯O and C-H⋯S contacts.

The effects of the Mo–Sn contact interface on the oxidation reaction of dimethyl ether to methyl formate at a low reaction temperature

With increasing degrees of Mo–Sn interface contact, the molar ratio of methyl formate (MF) to methanol (MeOH) and formaldehyde (FA) was found to linearly increase simultaneously.

Ternary and quaternary Ni(Si)Ge(Sn) contact formation for highly strained Ge p- and n-MOSFETs

The formation of new ternary NiGeSn and quaternary NiSiGeSn alloys has been investigated to fabricate metallic contacts on high Sn content, potentially direct bandgap group IV semiconductors. (Si)GeSn layers were pseudomorphically grown on Ge buffered Si(001) by reduced pressure chemical vapor deposition. Ni, i.e. the metal of choice for source/drain metallization in Si nanoelectronics, is employed for the stano-(silicon)-germanidation of highly strained (Si)GeSn alloys. We show that NiGeSn on GeSn layers change phase from well-oriented Ni5(GeSn)3 to poly-crystalline Ni1(GeSn)1 at very low annealing temperatures. A large range of GeSn compositions with Sn concentrations up to 12 at.%, and SiGeSn ternaries with large Si and Sn compositions from 18%/3% to 4%/11% are investigated. In addition, the sheet resistance, of importance for electronic or optoelectronic device contacts, is quantified. The incorporation of Si extends the thermal stability of the resulting low resistive quaternary phase compared to their NiGeSn counterparts.

The different roles of contact materials between oxidation interlayer and doping effect for high performance ZnO thin film transistors

To improve the performance of ZnO thin film transistors (TFTs) by using appropriate metal contacts, the different roles of contact materials between oxidation interlayer and doping effect are investigated. With careful characterization, an oxidation interlayer has been verified at the interface between ZnO film and Al or Ti contact, which is suggested to be responsible for contact resistance and thermal reliability. On the other hand, it is observed that the doping effect is the main reason for the Sn or Cu contact characteristics. The superior contact using Sn is due to an oxidation-free interface, donor doping effect, and a low barrier height. By using a metal contact with a high Gibbs free energy, the metal layer would hardly consume oxygen from channel layer during sputtering and easily form no oxidation interlayer. Thus, choosing a metal contact is important when fabricating high-performance metal-oxide TFTs for flat-panel displays.

A Resonant Cold-Electron Bolometer With a Kinetic Inductance Nanofilter

A novel type of resonant cold-electron bolometer (RCEB) is proposed. In this sensor, the internal resonance is organized by the kinetic inductance of an ultrasmall NbN superconducting nanostrip and the capacitance of the nanoscale superconductor-insulator-normal (SIN) tunnel junction. The size of kinetic inductance is about 300 times smaller than the size of geometrical inductance of the same value. This reduction of size gives an opportunity to create nanofilters with a total size considerably smaller than the wavelength. This internal resonance acts as a bandpass filter (instead of external filters) with a bandwidth of 3%-50%, something needed for radioastronomy applications. The use of NbN as Andreev contact material against escaping hot quasiparticles provides a unique opportunity to create an optimal CEB with only one SIN junction and an Andreev SN contact for thermal protection, in contrast to a classical CEB with two SIN junctions. The problem of hot quasiparticles escaping over the Andreev barrier (Δ) for Al electrode is overcome here by creating a barrier higher than quantum energy Δ > hf to have working kinetic inductance. Replacing two SIN junctions by one junction, we could use this junction of half the area to keep the same capacitive coupling. Therefore, a single-junction RCEB would have four times less area of junctions (and volume of absorber) in comparison with a two-junction RCEB and should show better noise performance due to the proportionally decreased e-ph (electron-phonon) noise component. The RCEB can be effectively used to create multiband elements that are actual tasks in submillimeter astronomy due to the benefit that comes from its ability to use co-located data, and problems with the dramatic increase of the size of the focal plane.

Adsorption of Sn (II) from Aqueous Solutions on Expanded Graphite

Expanded graphite (EG) was prepared by microwave irradiation at 1000 w for 60 s. It is a novel adsorbent for Sn (Ⅱ) adsorption. This paper aims to investigate the effect of the adsorption of EG. The adsorption behavior of Sn (Ⅱ) from aqueous solution onto EG was investigated with variety of parameters such as pH, adsorbents dosage, initial Sn (Ⅱ) concentration, contact time and temperature. On conditions that the pH was 2.5, the dosage of adsorbent was 0.02 g, the concentration of Sn (Ⅱ) was 200 mg/L and the temperature was 15°C, the maximum removal rate can reach to 98.32%, and the adsorption quantity can reach to 245.7985 mg•g-1. The results showed that the EG was an efficient and novel adsorbent for the removal of stannum from aqueous solution.

Spin-Hall current and spin polarization in an electrically biased SNS Josephson junction

Periodic in time spin-Hall current and spin polarization induced by a dc electric bias has been calculated in a superconductor-normal 2DEG-superconductor (SNS) Josephson junction. We assumed that the band energies of electrons in the normal system are splitted due to Rashba spin-orbit coupling. The transport parameters have been calculated within the diffusion approximation and using perturbation expansion over a small SN contact transparency. We found out that in contrast to the stationary Josephson effect, the spin-Hall current does not turn to zero. Besides a direct proximity effect caused by Cooper pair's transition into a triplet state, the spin current and polarization are also driven by a periodic electric field associated with the charge imbalance.

Degradation by Sn diffusion applied to surface mounting with Ag-epoxy conductive adhesive with joining pressure

Shear and tensile tests were carried out on joints made with an isotropic conductive adhesive (ICA) consisting of Ag and epoxy: Sn–Pb plated components mounted on printed boards and tensile bars consisting of Sn plated Ni and Cu joined under various joining pressures. After 150 °C–100 h, shear strength degraded to 72% and Sn in the plating diffused slightly to the Ag fillers in the ICA for the component mounting. High joining pressure increased the initial tensile strength and volume percentage of Ag fillers in the ICA. After 150 °C–100 h, tensile strengths for all joining pressures degraded on average to 36% of the initial strengths. In the case of low joining pressures, an Ag–Sn intermetallic was formed at only the Ag–Sn contact points of the Sn/ICA interface; leading to reproducibility of the component mounting. The difference of degradation ratios between the mounted components and tensile bars could be explained by the offset of the Sn–Pb area at the component/ICA interface.

Stabilization of a Dialkylstannylene by Unusual B−H···Sn γ-Agostic-Type Interactions. A Structural, Spectroscopic, and DFT Study

The reaction between SnCl2 and the lithium salt [[{nPr2P(BH3)}(Me3Si)CCH2]Li(THF)2]2 yields the cyclic dialkylstannylene [{nPr2P(BH3)}(Me3Si)CCH2]2Sn (6) as a 1:1 mixture of rac and meso diastereomers. Fractional crystallization from n-hexane gives samples of pure rac-6 and meso-6 which have been studied by X-ray crystallography, UV/visible, infrared, and multi-element NMR spectroscopy. In the solid state, rac-6 exhibits two short agostic-type B−H···Sn contacts, one to each BH3 group, whereas meso-6, in which both BH3 groups lie on the same side of the heterocycle, exhibits a single B−H···Sn contact. Multi-element and variable-temperature NMR spectroscopy suggests that these contacts persist in solution, resulting in unusual 119Sn chemical shifts of 587 and 787 ppm for the rac and meso diastereomers, respectively, significantly upfield in comparison to other dialkylstannylenes. Variable-temperature 1H, 31P{1H}, and 11B{1H} NMR studies reveal dynamic equilibria for the meso diastereomer involving competitive binding of the two BH3 groups to the electron-deficient tin center and restricted rotation about the P−C bond of the free phosphine−borane group. DFT studies confirm that the B−H···Sn contacts are an integral part of the structures; the HOMO and LUMO of both stereoisomers are comprised of an orbital of essentially 5s character on tin and an orbital of predominantly 5p character on tin perpendicular to the plane of the heterocycle, respectively. There is significant donation of electron density from the B−H σ-bonds to the vacant 5p orbital on tin; these B−H···Sn interactions stabilize the electron-deficient Sn(II) center by 30 kcal mol-1 for meso-6 and 40 kcal mol-1 for rac-6.

Kinetics of Sn(II) Contact Reduction in Alkaline Solutions with Compact and Dispersed Aluminum

The kinetics of contact reduction of tin on aluminum from alkaline stannite solutions was studied by atomic absorption analysis, iodometry, gravimetry, X-ray phase analysis, and method of polarization diagrams.

Dry etching of all-oxide transparent thin film memory transistors

Transparent ferroelectric field-effect transistors of oxidic thin films have been fabricated, showing a memory effect with an on/off ratio of the channel conductance of more than three orders of magnitude. The devices consist of a 10 nm n-type SnO2:Sb semiconductor channel with a 10 nm BaZrO3 capping layer, In2O3:Sn contact pads, a 250 nm PbZr0.2Ti0.8O3 layer as a ferroelectric insulator, and conducting SrRuO3 as gate electrode. After deposition, the layers were structured by means of reactive ion etching. All materials were structured with a lithographically defined mask in a CHF3Ar plasma. Etching with CHF3Ar does not produce any volatile etch products but contrary to pure Ar sputter etching, no redeposited materials were found on the structures.

The importance of the Pd to Sn ratio and of annealing cycles on the performance of Pd/Sn ohmiccontacts to n-GaAs

A novel Pd/Sn ohmic contact system has been developed for n-GaAs. The Pd to Sn ratio and annealing cycles have a significant effect on the performance of the contacts. Scanning electron microscopy (SEM) is employed to investigate the surface morphology of the contacts. Contact depthprofiles are analysed by secondary ion mass spectrometry (SIMS). Contact resistivities ρ c of the proposed metallization are measured utilizing a conventional transmission line model(TLM) method. Annealing at 360 °C for 30 min yielded the lowest ρ c of approximately 3.26 × 10 −5 Θ cm 2 on 2 × 10 18 cm −3 n-GaAs with a Pd(300 Å)/Sn(1500 Å) contact, whereas a Pd(300 Å)/Sn(900 Å) contact showsa lowest ρ c value of 6.05 × 10 −5 Θ cm 2 under the same annealing condition. Two-step annealing improves the contact properties. A lowest ρ c of approximately 1.49 × 10 −5 Θ cm 2 is obtained with a Pd(300 Å)/Sn(1500 Å) contact aftertwo-step annealing. The mass spectrometer analysis confirms the formation of PdGa and SnGa compounds at the lowest ρ c. Energy dispersive analysis of X-ray (EDAX) spectra show a correlation among Ga signal peaks and measured ρ c values at various annealing temperatures. The experimental data suggest a replacement mechanism in which an n +-GaAs surface region is formed by solid-phase epitaxy of Sn when Sn occupies excess Ga vacancies.

Effects of Au overlayers on the electrical and morphological characteristics of Pd/Sn ohmic contacts to n-GaAs

The effects of Au overlayers on the electrical and morphological characteristics of non-alloyed Pd/Sn Ohmic contacts to n-GaAs have been studied. Surface morphology of the contacts is investigated using surface profilometry measurements and scanning electron microscopy. Contact resistivities, ϱ e, of the proposed metallizations are measured using the conventional transmission line model method. A lowest ϱ e of ∼ 2.07 × 10 −5 Ω cm 2 is obtained with a Pd(50nm)/Sn(125 nm) contact on 2 × 10 18 cm −3 n-GaAs after annealing at 400 °C for 30 min under a forming gas atmosphere. An overlayer of Au improves both electrical and morphological characteristics of the Pd/Sn contacts. The Au overlayer also changes the optimal annealing cycles all the lowest ϱ e points. A Pd(50 nm)/Sn(125 nm)/Au(40 nm) contact shows a lowest ϱ e of ∼ 5.10 × 10 −6 Ω cm 2 after annealing at 330 °C for 30 min. The Pd(30 nm)/Sn(150nm)/Au(100 nm) contact shows a lowest ϱ e of ∼ 3.89 × 10 −6 Ω cm 2 after annealing at 330 °C for 30 min.

Triphenyltin Esters ofN-(2-Carboxybenzylidene)anilines: Synthesis, Spectroscopic Characterization, X-ray Structure Analysis and Fungicidal Activity

Four triphenyltin carboxylates formulated as o-Ph3SnOCOC6H4CH=N–Ar (Ar=C6H5; p-CH3C6H4; o-CH3C6H4; o-HOC6H4) were prepared and spectroscopically characterized. The crystal structure of o-Ph3SnOCOC6 H4CH=NC6H5 indicates that the tin atom, in each of the two molecules comprising the asymmetric unit, exists in a distorted tetrahedral geometry owing to an intramolecular acyl O. . .Sn contact. These new triphenyltin carboxylates display marked toxicity against the fungus Ceratocystis ulmi.

Comparison of pd/sn and pd/sn/au thin-film Systems for Device Metallization

AbstractAn Ohmic contact system comprising of Pd/Sn metallization has been developed for n-GaAs and compared with Pd/Sn/Au metallization. Surface morphology of the contacts is investigated using surface profilometry measurements and Scanning Electron Microscopy (SEM). The contact depth profiles are analyzed by Secondary Ion Mass Spectrometry (SIMS). Contact resistivities, Pc, of the proposed metallizations are measured using a conventional Transmission Line Model (TLM) method. A lowest ρc, of ∼2.07×10−5 Ω-cm2 was obtained with a Pd(50 nm)/Sn(125 nm) contact on 2×1018 cm−3 n-GaAs after annealing at 400 °C for 30 min. A Au overlayer improves the characteristics of the Pd/Sn contacts. The Pd(50 nm)/Sn(125 nm)/Au(100 nm) contact shows a lowest ρc of ∼1.29×10−6 Ω-cm2 after annealing at 330 °C for 30 min. The Pd/Sn/Au contacts exhibit superior properties compared to those of alloyed five-layer Au/Ge/Au/Ni/Au contacts.

Synthesis and Characterisation of N,N′‐Disubstituted 1,2‐phenylenebis(amido)tin(II) Compounds; X‐Ray structures of 1,2‐ and of [1,2‐ (tmeda)

AbstractCyclic bis(amido)tin(II) compounds 1,2‐ [R = SiMe3] (4), SiMe2But (5) and CH2But (6)], as well as (4)2(μ‐tmeda) 7 have been obtained either from (i) the corresponding dilithium compound 1,2‐C6H4[N(R)Li]2 1–3 and SnCl2 for 4–6, respectively, (or for 4) 2 1 + [Sn(μ‐Cl){N(SiMe3)2}]2; or (ii) 1,2‐C6H4[N(H)R]2 + Sn[N(SiMe3)2]2 for 4–6; or for 7 from 4 and tmeda. Compounds 4–6 are monomeric, yellow, thermochromic (becoming redder on heating), diamagnetic, crystalline and are lipophilic and sublimable in vacuo. Compound 7 is colourless. The molecular structures of 6 and 7 have been determined from single crystal X‐ray diffraction data. Compound 6 crystallises in bimolecular aggregates, in which there is a weak η‐C6 … Sn contact.

Zwei Extreme in der Zinnchemie: Ein nichtbindender Sn–Sn‐Abstand von 285 pm und eine 119Sn‐NMR‐Verschiebung δ = 3301 in metallorganischen Derivaten von Sn(0)

Two Extremes in Tin Chemistry: A Non‐bonding Sn–Sn Distance of 285 pm and a 119Sn‐NMR Shift δ = 3301 in Organome‐tallic Derivatives of Sn(0)The reaction of Na[{Cp'(CO)2Mn}2H] with SnCl2, which produces the inidene compound [Cp'(CO)2Mn\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ {\rm C}\ddot - {\rm C} $\end{document}Sn(Cl)\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ {\rm C}\ddot - {\rm C} $\end{document}Mn‐(CO)2Cp']− under standard workup procedures, results in the formation of [{Cp'(CO)2MnSn}2{μ2‐Mn(CO)2Cp'}2{μ2‐Cl}]− (1) when quenched with unpolar solvents. While, formally, 1 contains tin in its oxidation state zero, it may be conceived as composed of an Sn2−2 entity, which is linearly end‐on coordinated to two Cp'(CO)2Mn 16‐electron species; in addition the tin centers are bridged by two μ2‐Mn(CO)2Cp' moieties and a μ2‐Cl function. The resulting connectivity Sn2{μ2‐Mn(CO)2Cp'}2{μ2‐Cl} thus corresponds to a [1.1.1]propellane scaffolding. While there is no obvious need for a tin‐tin bond in this propellane‐type cage, a short Sn–Sn contact of only 285 pm is observed. While the 119Sn‐NMR signal of 1 could not be recorded, the peculiar bonding in this type of compounds is generally mirrored in their unconventional 119Sn‐NMR shift whereever signals can be observed: it is found that [{Cp*(CO)2Mn}3(μ3‐Sn)], which contains trigonally planar‐coordinated μ3‐Sn as a naked ligand atom, has its 119Sn‐NMR resonance at δ = 3301 well beyond the known range of 119Sn‐NMR shifts. This finding is interpreted in terms of a relatively week Snpπ‐Mndπ π bonding which leads to low‐energy unoccupied molecular orbitals as the prerequisit for a large paramagnetic contribution to the NMR shift.