bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation, Characterization and Application of Noble-Metal Colloids Stabilized By Chiral Molecules
Authors: Takase Mai , Kimura Shunsuke , Ohtani Bunsho 
Published: February 2020

Gold or platinum colloids stabilized with chiral compounds having a hydroxyl or amino group and multiple carboxylic acids (CHMCA) were prepared by a modified citric-acid method in which L-, D- or DL-tartaric acid, L-, D- or DL-malic acid were used instead of citric acid. Controlling the molar ratio to metal and concentration of CHMCAs and pH of the reaction mixture during the colloid preparation process, CHMCA-stabilized gold or platinum colloids, without giving precipitates even when stored for long time, was successfully prepared.
The CHMCA-stabilized gold colloids showed a photoabsorption peak at arou nd 520 nm, corresponding to the particle size of a few tens nanometer, and assigned to the surface plasmon resonance (SPR) and a peak in the circular dichromic spectra in the wavelength region of the SPR absorption though CHMCAs have no absorption there (Fig. 1). These results suggest that CHMCA-modified metal nanoparticles, i.e., "chiral surface plasmon resonance (cSPR)" depending on adsorption rotation direction of circularly polarized light. Application of the gold and platinum colloids loaded onto e.g., titania particles, to catalysis and photocatalysis using cSPR is discussed.
Bis-Metal Coordination Chemistry of Doubly N-Confused Hexaphyrins
Authors: Furuta Hiroyuki 
Published: February 2020

Expanded porphyrins have been received great interest due to the extended p-conjugation, multi-metal coordination, and multiple oxidation states, which consequently make them to be useful for optoelectronic applications, especially in the near-infrared (NIR) region. In contrast to the standard porphyrin with rigid planarity, expanded porphyrins are generally rather flexible and show the uncommon electronic and/or electromagnetic behaviors. However, the large flexibility of the molecules allows them to take various structures with many conformers and tautomers, which sometimes makes the metal coordination difficult and unpredictable. Thus, it has been awaited to synthesize the rigid-shaped expanded porphyrins possessing a large cavity that can accept bis-metals in the core without difficulty. Considering how enormous the achievement of porphyrin chemistry with a single metal is, the development of NIR dye chemistry with bis-metal expanded porphyrin ligands should be promising.
We have been working on N-confused porphyrinoids and exploring the unique features in view of their structures and electronic states.1 Replacing the regular pyrrole with N-confused pyrrole ring in the pyrrolic macrocycle, which we call “confusion approach”, is now recognized an effective strategy for controlling the electronic state and molecular shape (Figure 1).2 Recently, we have succeeded in synthesizing the singly, doubly, and triply N-confused [26]hexaphyrins and revealed the effects of confusion on the structures, optical properties, and metal coordination.3-7In this presentation, recent progress of the coordination chemistry of doubly N-confused hexaphyrins is overviewed.

References

1) Toganoh, M.; Furuta, H. Chem. Commun. 2012, 48, 937. 2) Srinivasan, A.; Furuta, H. Acc. Chem. Res.
2005, 38, 10. 3) Gokulnath, S.; Nishimura, K.; Toganoh, M.; Mori, S.; Furuta, H. Angew. Chem. Int. Ed.
2013
, 52, 6940. 4) Gokulnath, S.; Toganoh, M.: Yamaguchi, K.;

Mori, S.; Uno, H.; Furuta, H. Dalton Trans. 2012, 41, 6283. 5) Gokulnath, S.; Yamaguchi, K.; Toganoh, M.; Mori, S.; Uno, H.; Furuta, H. Angew. Chem. Int. Ed. 2011, 50, 2302. 6) Ikawa, Y.; Takeda, M.; Suzuki, M.; Osuka, A.; Furuta, H. Chem. Commun.
2010, 46, 5689. 7) Xie, Y.-S.; Yamaguchi, K.; Toganoh, M.; Uno, H.; Suzuki, M.; Mori, S.; Saito, S.; Osuka, A.; Furuta, H. Angew. Chem. Int. Ed.
2009, 48, 5496.
An Etch Stop and Sacrificial Materials Study for 3D NEMS-CMOS Co-Integration
Authors: Philippe Julien , Ouerghi Issam , Pollet Olivier , Hentz Sébastien , Arcamone Julien , Ernst Thomas 
Published: February 2020

In this paper, we compare several materials that can be used as sacrificial and etch stop layer for 3D NEMS-CMOS co-integration.
During these last 10 years Very Large Scale Integration techniques, well developed for transistors, have been used for the M/NEMS world (Micro/Nano Electro-Mechanical Systems). This allowed the construction of various kinds of miniaturized nano-sensors, especially resonators that can be used for gas sensing, mass spectrometry and molecules recognition for example [1,2]. Nevertheless, the use of such nano-sensors requires a CMOS electronic circuit for the readout part and for the oscillating-loop creation with the nano-resonator. The CMOS part can be on a separated die linked to the NEMS resonator using wire bonding connections (Fig.1-a).
However, in order to reduce signal transmission loss and allows the fabrication of a sensor with a high density of resonator, the best approach consists in processing both NEMS and CMOS on the same die (Fig.1-b and c) [3,4], in particular following a 3D scheme (Fig.1-c) [5,6]. The NEMS release process, commonly performed by a HF (Hydrogen Fluoride) vapor etching operation, is the final step of the integration. It implies the selection of two kinds of materials. The first one is a sacrificial layer in order to achieve a well-controlled and clean release of the mechanical structure. The second one is an etch stop layer located between the NEMS and CMOS for protecting all the area under the nano-resonator (Fig.2). In such 3D approach, etch stop and sacrificial layers can be deposited at high temperature before the molecular bonding of the mechanical part with the electronic part.
Two parameters are critical for the selection of those materials; the etch rate and the presence and dimensions of the residues (see Fig.3, 4, 5 and 6) which may result from a silicon-fluorine complex precipitation during the etching process [7]. These residues must not disturb the mechanical resonator during its oscillations.
This paper will present results about etch-rates and residual dimensions on HF vapor etching of materials used for the NEMS realization. It is shown in Fig.3 and Fig.6 that USG (Undoped Silicon Glass) and SiH4, usually used in back-end processes, are not suitable for the vapor HF release contrary to TEOS (tetraethyl-orthosilicate) Low Rate (LR) and boron-nitride (BN). Our study shows that the latter constitutes a good etch stop layer for HF vapor processing within a 3D integration scheme.
[1] J. Arcamone et al, IEDM 2011 IEEE International, pp.29.3.1, 29.3.4, 5-7 Dec. 2011
[2] Y.T. Yang et al, Nano lett., Vol. 6, No. 4, Apr. 2006
[3] E.Ollier et al, MEMS 2012
[4] J. Arcamone et al, Tech. Digest. IEDM 2012, pp. 15.4.1-15.4.4
[5] P.Batude et al, J.Emerging Sel. Top.Circuits Syst, Vol.2, No.4, Dec. 2012
[6] J-C. Souriau, IEEE Trans. Compon., Packag. Manuf. Technol. Vol. 1, No.6, June 2011
[7] H. Ritala et al, ECS Trans. 2009 25(5): 355-358
Comparison between Equilibrium Voltage Step and Charge Pumping Techniques for Characterizing near Si-SiO2 Interface Traps
Authors: Guenifi Naima , Bauza Daniel 
Published: February 2020

In conventional MOS structures, the interface region between silicon and its oxide contains defects which play an important role in the performance and reliability of the devices by acting as charge traps. Traps having response times greater than that of conventional (and so-called “fast”) interface traps are known as slow traps. These traps are supposed to exchange charges with the semiconductor by tunnelling, their response time depending on their energy level and distance from the interface. Due to their wide range of response times and depending on the measurement technique employed, they are often indistinguishable from fast ones or from fixed oxide charges.
Several techniques have been used to characterize electrically these different kinds of traps in MOS capacitors or MOSFET structures. Recently, the study on MOS capacitors of current transients that follow the application of a small gate voltage step due to the change in the charge state of the traps has been proposed by Tanner & al. [1]. The technique was used to characterize traps generated in the oxide by constant current stressing [1]. A few years later, Spillane et al. [2] introduced the McWhorter tunnelling model [3] to evaluate oxide depth from the traps time constant and study the slow states density versus oxide depth.
In this paper, after recalling the principle of the Equilibrium Voltage Step (EVS) technique, this technique is used to extract the profile in three dimensions (Nt, x, E) of the trap density near the Si-SiO2interface of a lightly stressed MOS structure (Fig. 1). This has been achieved using the models depicted in Refs. [2] and [4] using a device with a rather low interface states density.
These results are summarized in two dimensions (Nt,x) in Fig. 2 where they are compared with those obtained with charge pumping (CP) [4], [5]. A good coherence between the results recorded using the two techniques is obtained. The traps densities measured using EVS are in the same order of magnitude as those obtained with CP. Both trap profiles show the same tendencies even though their shapes are somewhat different. From that point of view, CP may be more efficient in distinguishing between interface and near oxide traps. However, the shape of trap profiles extracted previously using current-DLTS [6] is very close to that measured here using EVS method. In this paper, these results will be compared and discussed.
[1] P. Tanner, S. Dimitrijev, and H.B. Harrison, Electronics Letters, 31, 1880 (1995).
[2] M. P. Spillane, S. Taylor and M. J. Uren, Microelectronic Engineering, 48, 155 (1999).
[3] A. L. McWhorter, Semiconductor Surface Physics, Univ. Pennsylvania Press, 1957, pp. 207-228.

[4] D. Bauza and Y. Maneglia, IEEE Trans. Electron Devices, 44, 2262 (1997).
[5] Y. Maneglia, F. Rahmoune and D. Bauza, J. Appl. Phys., 97, 145021 (2005).
[6] D. Bauza, J. Appl. Phys., 84, 6178 (1998).
A Cahn Hilliard Modeling of Metal Oxide Thin Films for Advanced CMP Applications
Authors: Basim G. Bahar , Sengul Yasemin , Karagoz Ayse 
Published: February 2020

Chemical mechanical planarization (CMP) process enables topographic selectivity through formation of a protective oxide thin film on the recessed locations of the deposited metal layer while a continuous chemical oxidation reaction is followed by mechanical abrasion takes place on the protruding locations [1]. This paper demonstrates a new approach to CMP process optimization in terms of slurry formulations by analyzing the nature of the protective metal oxide nano films and modeling their growth through a Cahn Hilliard Equation (CHE) approach [2]. The commonly utilized models on the material removal rate calculations are also revisited to address the differences from the typical approaches to the dynamic removal models at the elevated layers.
In previous work we have demonstrated the formation and mechanical properties of the chemically modified metal oxide thin films in CMP and discussed the stresses develop at the interfaces delineating the stability and protective nature of the chemically altered films [3]. The preliminary model is developed on the very well established tungsten films by assuming a constant temperature and metal oxide thin film volume to apply the CHE approach. As the CMP nano metal oxide films of tungsten have been shown to be self-protective, these assumptions are valid. Thin film analyses were conducted through XRD, XRR and FTIR characterization and compared to the theoretical calculations for the modeling simulations. The atomic force microscopy surface structures observed on the tungsten wafers are shown to be predicted by the CHE approach as spinodal decomposition structures. This new modeling approach is going to help in formulating optimal slurries for the new generation CMP materials by considering not only the active material removal concept but also the very critical planarization requirement through enabling protective oxide layers for planarization.
References:

Kaufman, F.B., Thomson, D.B. Broadie R.E., Jaso, M.A., Guthrie, W.L., Pearson, M.B., Small, M.B., Journal of the Electrochemical Society, 138,(1991) 3460.

Gamerio, M., Mischaikow, K., Wanner, T., Acta Materialia 53 (2005) 693-704.

Basim, G.B., Karagoz, A., Ozdemir, Z. ECS Trans. “Metal Oxide Nano Film Characterization for CMP Optimization” 50 (39) (2013) 3-7.
UV VIS Studies of Ce(III)/Ce(IV) Redox Reactions to Understand Abrasive and Work Surface Interactions during STI CMP
Authors: T.D. Umashankar , Ramanathan S 
Published: February 2020

In the current fabrication processes for integrated chips (IC), shallow trench isolation (STI) scheme is used to isolate and insulate transistors. Chemical mechanical planarization (CMP) is a key step in STI integration scheme. High selectivity slurries (HSS) which yield high silicon dioxide to silicon nitride polish rate are often used, and this is achieved by controlling the solid loading and the chemical concentration of additives [1]. Ceria based slurries with suitable additives are known to provide high selectivity [2, 3, 5]. Ceria is known to interact chemically with the silicon dioxide surface during CMP [2,3] and it is proposed that Ce(III) might play a role in the chemical interaction [4], but the exact nature of the species interacting with oxide are not known.
Addition of hydrogen peroxide (H2O2) to ceria based slurries is reported to suppress the oxide and nitride removal rates [4]. However, when other abrasives are employed, hydrogen peroxide does not modify the removal rate significantly [4]. Ce (III) and Ce (IV) ions are known to exhibit UV VIS absorption peak at different wavelength regions.
In this work a study on the kinetics of Ce (III) and Ce (IV) ions in the presence of H2O2is undertaken using UV-Visible Spectroscopy. Ce (III) chloride and Ce (IV) sulfate are employed for the initial study and the effect of hydrogen peroxide on changing the equilibrium composition is analyzed. The absorption is also monitored as a function of pH and time, to understand the dynamics of the system. Further, ceria abrasives are employed in the study and the nature of the species dissolving into the aqueous medium in presence of and absence of hydrogen peroxide, at different pH values are analyzed. The results show that the equilibrium between Ce (III) and Ce (IV) is shifted by the hydrogen peroxide which may help explain the suppression of oxide and nitride CMP rate by the addition of peroxide to ceria based slurries.
References:
1. J.M. Steigerwald, S.P. Murarka, R.J. Gutmann, Chemical Mechanical Planarization of Microelectronic Materials, John Wiley and Sons, New York, 1997.
2. L.M. Cook, Chemical process in glass polishing, J. Non-Cryst. Solids 120 (1990) 152–171.
3. L.Y. Wang, K.L. Zhang, Z.T. Song, et al., Ceria concentration effect on chemical mechanical polishing of optical glass, Appl. Surf. Sci. 253 (2007) 4951–4954.
4. R.Manivannan, S.Ramanathan, Appl Surf Sci.,Volume 255 (2009), 3764–3768
5. Naresh K. Penta, B.C. Peethala, S.V.Babu et al, Role of Hydrogen Bonding on the adsorption of several amino acids on SiO2 and Si3N4 and selective polishing of these materials using ceria dispersions, Colloids and Surfaces A : Physiochem. Eng. Apects 429(2013)67-73
(Invited) Reducing EOT and Interface Trap Densities of High-k/III-V Gate Stacks
Authors: Chobpattana Varistha , Mates Thomas , Mitchell William , Zhang Jack , Stemmer Susanne 
Published: February 2020

In0.53Ga0.47Asis currently being investigated as a channel material for III-V metal-oxide-semiconductor field effect transistors (MOSFETs) for post-Si complementary CMOS applications. A major obstacle facing the development of MOSFETs with In0.53Ga0.47As channels is the high density of traps (Dit
) at the gate dielectric/III-V semiconductor interface. Interface trap densities are relatively straightforward to detect for In0.53Ga0.47As channels, because of its narrow band gap (0.75 eV); at room temperature they cause, for example, a frequency-dependent hump in the depletion region of capacitance-voltage (CV) characteristics, and peaks in normalized conductance maps. To reduce the large trap densities at interfaces between In0.53Ga0.47As and the gate dielectric (typically Al2O3 or HfO2) various surface preparation and passivation methods are currently being investigated in the literature.
In this presentation, we will discuss the development of novel, in-situ surface preparation methods prior to atomic layer deposition (ALD) of gate dielectrics on In0.53Ga0.47As, and their influence on EOT scaling and Dit
. The surface treatments employed here consist of in-situ cleaning involving alternating cycles of nitrogen plasma and trimethylaluminum (TMA) pulses prior to ALD of different dielectrics. We demonstrate metal-oxide-semiconductor capacitors (MOSCAPs) with HfO2 and HfO2/Al2O3 dielectrics with very low Dit
(in the low 1012 cm-2 eV-1 range) that can be scaled to sub-nm EOT (accumulation capacitances exceeding 3 µF/cm2 at 1 MHz for n-In0.53Ga0.47As). To elucidate the mechanisms by which these novel surface preparation methods allow for reducing both Dit
and EOT, we present complementary studies of the MOSCAP electrical properties (GV and CV), interface chemistry and surface morphology using XPS, TEM, SIMS and atom probe tomography, as a function of surface cleaning parameters. Because the surface preparation methods employed here allow for both low Dit
and low EOT, well behaved gate stacks can also be obtained on p-In0.53Ga0.47As channels. Comparisons of the CV results for p- and n-channels with calculated CV allow for analysis of the limitations of currently employed methods of Dit
analysis, such as the Terman method.
(Invited) 2.5D Advanced System-in-Package: Processes, Materials & Integration Aspects
Authors: Shenoy Ravindra V , Lai Kwan-Yu , Gusev Evgeni 
Published: February 2020

Over the next several years, the semiconductor roadmap presents several disruptive challenges:

the cost structure in terms of normalized cost per gate is changing dramatically. The conventional cost reduction from one node to the next is diminishing. Some of the advanced nodes are expected to end up costing more than the previous nodes due to increased process complexity and lithography steps

increasing number of features and new “More than Moore” functionalities need to be integrated

the end of CMOS scaling is going to lead to new devices & technologies for continuation of Moore’s law

While the above presents challenges for the conventional system on chip (SOC) integration, it presents an opportunity for advanced “2.5D system in package (SIP)” integration where multiple chips could be integrated on an interposer.
Silicon interposer technology with through silicon vias has been extensively explored and evaluated for 2.5D SIP integration. Successful integration of memory and logic chips on silicon interposer has been demonstrated. However, the commercialization of this technology into high volume mobile/consumer applications has been limited by cost. A number of alternative technologies are being actively explored for interposers. The talk will review new materials, processes and integration aspects of interposer based 2.5D advanced system in package.
Development of Non-Aqueous Redox Flow Batteries at Pacific Northwest National Laboratory
Authors: Wei Xiaoliang , Wang Wei , Cosimbescu Lelia , Xu Wu , Vijayakumar Murugesan , Liu Tianbiao , Shao Yuyan , Liu Jun , Sprenkle Vincent 
Published: February 2020

Redox flow battery (RFB) is considered as one of the most promising large-scale stationary energy storage technologies and has attracted much attention both academically and industrially. The unique cell architecture renders RFB with attractive advantages including separation of energy and power, exceptional design flexibility, excellent scalability and modularity, long service life, high efficiency, etc.Therefore, RFB is a well-suitable option to stabilize the power grid and tackle the intermittency of the renewable energies. Conventional aqueous RFBs have achieved significant progress such as vanadium-vanadium, iron-vanadium, zinc-bromine, polysulfide-bromine systems. However, aqueous RFBs also are confined by two major intrinsic limitations: narrow voltage window to avoid water electrolysis and relatively low concentrations of the electroactive materials, making them generally low energy density systems.
Non-aqueous electrolytes provide wider electrochemically stable voltage window and examples having cell potential of >2V have been demonstrated recently. The expansion of the operational cell potential has a direct impact on the energy density of the non-aqueous RFB system. Meanwhile, the wider voltage windows make more redox couples available as electroactive material choices and increase the possibility of using multiple electron transfer redox reactions. Therefore, a number of non-aqueous RFB systems have been proposed and investigated [1]. Most of these systems are based on organic active materials that have the advantages of convenient structural tunability and availability of different redox mechanisms.
Here we report the development of non-aqueous RFBs at PNNL with the focus on several lithium-organic RFB systems, each adopting a different organic cathode material [2]. Chemical functionalization to the organic active materials was carried out to increase its solubility targeting high energy density energy storage systems. The flow cells of these systems demonstrated excellent electrochemical performance with impressive cell efficiencies, high operational current density, and remarkable cycling stability that exceeded those of other reported non-aqueous RFBs. Effective protection of the lithium anode employed in these lithium-organic RFB systems will be discussed.

References

1. W. Wang, Q. Luo, B. Li, X. Wei, L. Li, Z. Yang, Adv. Funct. Mater., 23, 970 (2013).
2. W. Wang, W. Xu, L. Cosimbescu, D. Choi, L. Li, Z. Yang, Chem. Commun.
48, 6669 (2012).

Figure 1. A lithium – anthraquinone non-aqueous RFB: (a) CV curves of 0.25M structurally modified anthraquinone in 1.0M LiPF6/PC electrolyte with lithium foil as the reference electrode; (b) Cycling energy efficiency and discharge energy density. [2]