bluuebunny/crossref_metadata_2025_split huggingface dataset:
High TEC Copper to Connect Cu-Cu Pads for Wafer Bonding
Authors: Tran Anh , Hirato Tetsuji , Kondo Kazuo 
Published: December 2020

Introduction
Cu/SiO2 hybrid bonding is a promising method for 3D stacking of integrated circuits in which the copper bonding of the interconnection pads and direct bonding of the silicon dioxide surface occur simultaneously.1 This bonding technology requires a damascene-like process on each sample to be bonded (wafers and/or chips), including copper deposition and chemical mechanical polishing (CMP), in order to create the copper bonding pads and lines.2 Due to the higher erosion rate of copper in comparison with silicon dioxide, a dishing effect on the surface of copper is generated. This effect can prevent bonding and thereby lead to electrical connection failure between top and bottom pads. In order to overcome this dishing effect and enhance the copper bonding at lower temperature, we developed a high thermal expansion coefficient (TEC) electrodeposited copper.
Result and discussion
Figure 1 shows the thermal expansions of conventional copper (black line) and electrodeposited copper with the high TEC additives (red curve). For the conventional copper, the expansion length at 300oC is 69 μm. Meanwhile, the expansion length of high TEC copper at 300oC is 90 μm, 30% higher than conventional copper.
Figure 2 shows the variation of contact area with annealing temperature for 4 nm dishing depth of circular copper pad for conventional copper and high TEC copper. Contact area values are calculated by the model in numerical study of C. Sart et al.3. Copper pad width is 4 μm and thickness is 500 nm. It can be easily seen that the contact area with high TEC copper is significantly higher than conventional copper. At 200oC, the contact area of conventional copper is only 63.5 %. Meanwhile, the contact area of high TEC copper is 93.6 %. Furthermore, 100% contact area is possible from 250oC for circular copper pads with dishing depth 4 nm.
Reference

Rebhan et al., 17th Electronics Packaging and Technology Conference Proceedings, 1-4 (2015).

Beilliard et al., International Journal of Solids and Structures (2016). DOI: 10.1016/j.ijsolstr.2016.02.041

Sart et al., 6th Electronic System-Integration Technology Conference (ESTC) (2016). DOI: 10.1109/ESTC.2016.7764484

Figure 1
Intelligent MOL(Middle-Of-Line) Design Methodology for 3D FinFET Manufacturability
Authors: MIN Jeong Guk , Noh Sang Do , Choi Jaehyuk 
Published: December 2020

This research is an outstanding first study on the intelligent design methodology of the core MOL scheme. It can maximize the manufacturability of 3D FinFET technology that is mainly used for foundry AP products ranging from 10nm to 5nm.
In order to realize various MOL structures, 3D virtual process simulation considering plasma and surface reaction was implemented, and based on this, the generation of gate to contact short, a chronic defect in FinFET MOL scheme, could be detected without decap. Futhermore, for the feature selection, the process factor sensitivity analysis was performed with the Monte carlo algorithm, which is one of the representative reinforcement learning techniques, and it was found that the key factors of defect were gate to contact misalign and contact etch angle. In the Gate-to-Contact 3D minimum distance probability distribution function generated by millions of samplings based on this intelligent algorithm, the failure criteria can be obtained by mapping with the number of fail bits detected in the wafer.
As the device's scaling limit was reached, SCE-driven FEOL(Front-End-Of-Line) characteristics as well as the MOL parasitics' portion became very huge in the 10 nm or less FinFET technology, but all studies have been limited to the effects of device performance via RC(Resistance-Capacitance) analysis.
On the other hand, our methodology provides a 3D minimum distance 5.7nm specification for a defect-free MOL structure for the first time, and provides conditions to meet Gate to CNT short zero at the current process capability level when improving M/A 4.5nm and etch ang 1.5o. In silicon, the same result was obtained as predicted.

Figure 1
(Edward Goodrich Acheson Award Address) From Medical Applications to the Environment: The Important Role of Electrochemical Energy Storage
Authors: Takeuchi Esther S. 
Published: December 2020

There is critical need for advances in electrochemical energy storage as the technologies are often pivotal for the success of an application. For example, transportation, personal electronics and biomedical applications have ever increasing demands for portable power. Further, stationary energy storage may be a key factor in the ability to broadly integrate intermittent renewable energy sources such as wind and solar. Despite remarkable advances in electrochemically active materials over the last several decades, there remains an urgent need to enhance utilization efficiencies and to develop materials that can safely deliver both high power and energy density.
An existing challenge for each specific system of electric energy storage is understanding the basic science associated with the gap between the usable output of the energy storage system and its theoretical energy content. The goal of overcoming this inefficiency is to achieve more useful work (w) and minimize the generation of waste heat (q). Optimization can be approached at the macro level, where bulk parameters are identified and manipulated. However, such a strategy may not provide insight toward the complexities of electric energy storage, especially the inherent heterogeneity of ion and electron flux contributing to the local resistances at numerous interfaces found over several scale lengths within a battery.
We are pursuing the investigation of factors that affect ion and electron transport including properties of electroactive materials, interfaces, and electrode structures. Recent advances in the use of in-situ and operando characterization techniques with spatio-temporal resolution of electrochemical activity have enabled us to gain significant mechanistic insight. The ability to understand and ultimately tune these complex electrochemical systems to specific applications, both current and future, depends on specific experimentation and understanding over multiple length scales.
(Invited) 200mm GaN Power: Technology and Commercialization Status on Scalable QST® Platform
Authors: Odnoblyudov Vladimir , Aktas Ozgur , Basceri Cem 
Published: December 2020

In recent years, GaN has become a forefront wide bandgap semiconductor material for next-generation, energy-efficient power electronics. With its higher breakdown strength, faster switching speed and lower on-resistance, GaN power devices can convert power far more efficiently than Si-based devices. While its performance is commercially demonstrated, widespread GaN adoption requires a scalable and high-yielding manufacturable technology platform enabling economies of scale and a full spectrum of low-cost products such as lateral and vertical power switches extending from 100V to 1,200V and beyond, monolithic ICs and rectifiers.
QROMIS’ disruptive commercial solution to high volume, low cost and scalable GaN device manufacturing has been steadily gaining traction, owing to unique properties of specially-designed CMOS fab-friendly and semi-spec substrate called “QST®” (QROMIS Substrate Technology) with a core having a thermal expansion that very closely matches the thermal expansion of the GaN/AlGaN epitaxial layers. QST® enables breakage-free high-volume manufacturing of standard semi-spec thickness 200mm GaN device wafers (scalable to 300mm), covering all GaN applications including 100V-to-1800V high performance power devices, RF devices, and display microLEDs.
In this talk, the following status updates on 200mm QST®-based materials and device technologies will be presented: (1) commercial QST® substrate products, (2) commercial GaN-on-QST® epi-wafer products, including development studies on epi-wafers for 1,200V and beyond applications, (3) high-performance normally-off 650V p-GaN based GaN-on-QST® HEMT transistors & monolithic ICs (with integrated drivers and logic) fabricated in a CMOS fab and commercialization timelines, (4) 200mm GaN-on-QST® device foundry services for the industry players, and (5) initial high-performance GaN-on-QST® RF device results.
(Invited) Dye-Sensitized Photo Rechargeable Battery for Indoor Applications
Authors: Kwon Tae_Hyuk 
Published: December 2020

Dye-Sensitized Solar Cells (DSSCs) have great potentials owing to their aesthetic colors, transparency and low cost. Furthermore, they are favorable for indoor system, because DSSCs have great power conversion efficiency (PCE) at low light. However, there are still several problems in the practical applications. Therefore, our group suggested the new concepts of organic materials and devices for approaching to real application. For this aim, we developed dye-sensitized photo rechargeable solar battery for indoor light saving.
Until now, most of single-structured photo-rechargeable devices considered photo-charging process at high light intensity (mainly standard AM 1.5G sunlight). Furthermore, it is very difficult to combine dye-sensitized solar cells with lithium ion battery in a monolithic device because of their intrinsic mismatch energy levels of photo (-0.5 V vs NHE) and storage electrode (-3.0 V vs NHE). We came up with this intrinsic issues by using the overlithiation reaction of LiMn2O4 (ca. 0.0 V vs NHE) for energy storage and finally, achieved self-powered dye-sensitized photo rechargeable battery (DSPB, FTO/TiO2/Dye/Redox mediator/Pt-Li+ conducting separator/Li+ solution/ LixMn2O4) in monolithic devices, and suggested new concepts for energy recycle of indoor lightening. Next, we investigated the light intensity dependence of photo-charged energy density with different redox mediator (or charge regenerator for oxidized dye), such as I−/I3
−, Co2+/3+(bpy)3, Cu+/2+(dmp)2. Finally, the DSSBs were successfully working at low light intensity (11.5% of ηoverall at 0.15 mW cm−2 (500 lux)), operating the commercial IoT wireless sensor node using only indoor light sources.
Amorphous IGZO TFTs with Low Electrical Hysteresis By Using Two-Photomask Process
Authors: Li Zhen-Hao , Chiang Tsung-Che , Liu Po-Tsun , Kuo Yue 
Published: December 2020

Amorphous oxide semiconductor (AOS)-based TFTs have been considered as potential channel materials for high-resolution TFT-LCDs and AMOLEDs [1-3]. However, the electrical characteristics of AOS TFTs frequently deteriorate with increasing operating cycle times because of the increased trap states present in the AOS semiconductor layer. In this work, we demonstrated the amorphous Indium-Gallium-Zinc-oxide (a-IGZO) TFT fabricated by using two-photomask process [4], which can effectively reduce the process complexity and manufacture cost.
Experiment
The TFT manufacture processes are as followed. A Mo film was deposited by DC sputtering on glass substrate as gate electrode. After patterning, the tri-layer structure of HfO2 /IGZO/ HfO2 film was deposited as gate insulator, channel and passivation layer respectively. The pattern of channel and passivation layer was defined by photolithography with back exposure. Finally, using DC sputtering deposited the MO films and patterned to form the source/drain electrode.
Result and Discussion
In this work, experimental results have shown that the 2-photomask fabricated a-IGZO TFT can exhibit superior performance with a subthreshold swing of 66 mV/dec., threshold voltage of -0.37V, field effect mobility of 10 cm2/V∙S, Ion/Ioff current ratio of ~107 and extremely low electrical hysteresis loop ∆V=10mV was obtained. The reliability of a-IGZO TFTs also was measured and investigated, it reveals the great reliability because the passivation layer can effectively isolate the reaction between the back-channel and atmosphere. It is highly promising to be applied for the emerging transparent display backplane technologies.
Reference
[1] K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano, and H. Hosono, nature, vol. 432, no. 7016, pp. 488-492, 2004.
[2] J. Yao, N. Xu, S. Deng, J. Chen, J. She, H.P. D. Shieh, P.T. Liu, and Y.P. Huang, IEEE Transactions on Electron Devices, vol. 58, no. 4, pp. 1121-1126, 2011.
[3] P.Y. Kuo, C.M. Chang, I.H. Liu, and P.T. Liu, Scientific reports, vol. 9, no. 1, pp. 1-7, 2019.
[4] Y. Kuo, Journal of The Electrochemical Society, vol. 138, no. 2, pp. 637, 1991.

Figure 1
New Degradation Model of LTPs TFT Aged Off-State Bias Stress on Flexible Substrate
Authors: Kim Kihwan , Kim Soonkon , Song Minjun , Kim Hyojung , Kim Yongjo , Choi Byoung Deog 
Published: December 2020

We conducted experimental and quantitative studies on the effects of off-state bias stress of the p-type polycrystalline silicon thin film transistors (TFTs) on flexible substrate and presented a new degradation model using TCAD simulation. In the off-state bias stress condition, the gate induced drain leakage (GIDL) current is determined by the gate and drain voltage (Vgd) and gate bias stress above a certain bias is accompanied by a change in Vth. To understand and model the underlying mechanism of these results, we developed a spatial probability analysis model with mapping of physical quantity (SPAM). The spatial distribution the E-field and the electron concentration are considered as degradation factors, and are used in the equations for defect creation (DC) and charge trapping (CT) TCAD model. We had to implement different forms of aging model in the two regions: 1) CT in poly-Si/SiOX interface, and 2) DC in the channel bulk (especially, the grain boundary). Finally, our new degradation model allows us to analyze how the GIDL current decreases with various aging conditions and provides a quantitative relationship between the amount of charge trapping and the amount of defect creation
I. Fixed negative charge (-) of interface of poly-Si/SiOx
(ε(x,y) > εC,f and n(x,y)> nC,f)
Qfix
(-) (x,y)=αf *[{ε(x,y)-εC,f}/εm,f ]γf_field
*[log{n(x,y)/nC,f }]γfn

II. Ionized defect density of channel bulk (Grain and GB)
(ε(x,y,z) > εC,tA )
NtA
(-) =gtA (ε)*exp[-{(EtA-EGA)/WGA}2 ]
gtA (ε)= αtA*[{ε(x,y,z)-εC,tA}/εm,tAm ]γtA

Figure 1
High-Performance Thin-Film Transistors Enable By Metal Oxide Semiconductor with Polyaniline Doing in the Channel Layer
Authors: Lee Eun Goo , Lee Jaehak , Lee Sung-Eun , Na Hyun-Jae , Kim Kyungho , Kim Youn Sang 
Published: December 2020

Thin-film transistors(TFTs) using metal oxide-based semiconductors have attracted much attention because of their high carrier mobility, excellent optical transparency, low process temperature and solution process. In particular, indium oxide(InO
x
) is capable of aqueous routes for environmentally friendly and shows excellent carrier transport due to high carrier concentrations. Despite these advantages, pristine InO
x
films are generally polycrystalline structures, making it difficult to apply to flexible electronics, and it is necessary to adjust the carrier density to improve stability. Moreover, such a polycrystalline thin film does not exhibit uniform threshold voltage and field-effect mobility, making it difficult to enlarge the device. To address this problems, InO
x
was doped with inorganic materials such as Ga, Zn, Sn and Sc. Since the thin film transistors using these amorphous metal oxide semiconductor lowers the carrier density, it adversely affects carrier mobility.
In order to solve the doping problem of the conventional inorganic material that lowers the carrier mobility, we proposed solution-processed polyaniline doping in the channel layer of metal oxide semiconductors. As a result, depending on the polymer concentration inside the metal oxide semiconductor, the crystallinity of the InO
x
film decreases and the carrier concentration is controlled, affecting electrical properties such as field-effect mobility, on / off ratio, onset voltage and hysteresis. These results show the possible applicability to the industrial field as well as a significant meaning in improving the properties with polymer doping in the solution-processed metal oxide semiconductor at low temperatures.
(Invited) Photon Upconversion and Triplet Dynamic Nuclear Polarization in MOFs
Authors: Yanai Nobuhiro 
Published: December 2020

Photon upconversion (UC) is the key technology to overcome the thermodynamic efficiency limit of solar energy conversion devices. Triplet-triplet annihilation (TTA)-based UC has drawn increasing attention in recent years, primarily because of its occurrence under low-intensity, noncoherent light excitation. However, the application of TTA-UC has been significantly hampered by the slow diffusion of excited molecules in solid matrices. The use of emitter-based metal–organic frameworks (MOFs) allows the fast triplet exciton diffusion among the regularly aligned emitter chromophores. Besides, near-infrared (NIR)-to-visible (vis) TTA-UC is very important for various applications, however, it remains challenging mainly due to the energy loss during the S1-to-T1 intersystem crossing (ISC) of molecular sensitizers. We circumvent this energy loss by employing a sensitizer with direct singlet-to-triplet (S-T) absorption in the NIR region. We achieve the NIR-to-visible TTA-UC in the solid-state by introducing the S-T absorption sensitizer into emitter-based MOFs.
Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are powerful and versatile methods in modern chemistry and biology fields. Nevertheless, they suffer from intrinsically limited sensitivity due to the low nuclear spin polarization at ambient temperature. One of the promising methods to overcome this limitation is dynamic nuclear polarization based on photo-excited triplet (triplet-DNP) that allows the hyperpolarization at room temperature. Previous studies of triplet-DNP have been limited to dense crystalline and amorphous materials, and it remains difficult to hyperpolarize biology-relevant probes. To overcome this limitation, we introduce the chemistry of MOFs to the field of triplet-DNP. The nanoporous structure of MOFs allows the accommodation of polarizing agents as well as other guest molecules. This work paves the way towards the hyperpolarization of various probe molecules at room temperature for imaging applications.
(Keynote) Electromagnetic Field Stimulated MOFs
Authors: Knebel Alexander , Chen Donghui , Hosseinimonjezi Bahram , Santos Jaciara C. C. , Redel Engelbert , Caro Jürgen , Volkmer Dirk , Woell Christof 
Published: December 2020

Electromagnetic, external stimuli can be used to switch Metal-Organic Framework (MOF) materials and to achieve control over the pores of these materials on different ways. We designed MOFs with switchable moieties in their side-chains, such as azobenzene, to be switchable under irradiation of UV/Vis light. Additionally, we developed devices to be able to measure the impact of electromagnetic fields in-situ. We focused on surface anchored MOF (SURMOF) thin films, deposited on asymmetric, porous α-Al2O3 supports as gas separation membrane layers. It is possible to control the gas transport properties of the materials using, but also using electric fields, and measure changes gas separation (permeability and selectivity) of binary mixtures in-situ, using the Wicke-Kallenbach technique. The light switchable systems were investigated on their CO2 separation performance: By switching the azobenzene between cis and trans isomers inside the pore windows, it was possible to switch dipolar moments, thus changing the adsorption properties towards the quadrupolar moment of CO2. Using electric fields of 500 V/mm we could show on the prominent example of ZIF-8, a zeolitic imidazolate framework, that it has a strong impact on the gas transport properties, especially looking at the molecular sieving. The mechanistic of the electric field influence on the ZIF is as follows: The electric field distorts the lattice of the MOF, shifting the Zn2+ ions, lowering the symmetry of the unit cell. This effect leads to polarized polymophs of the structure, sharpening the molecular sieving through a stiffening effect. The purification of Propylene/Propane, a highly desired separation for the plastics industry, could be increased through the electric field stimuli by 33%.
References

Knebel, A. et al. Defibrillation of soft porous metal-organic frameworks with electric fields. Science
358, 347–351; 10.1126/science.aal2456 (2017).

Wang, Z. et al. Tunable molecular separation by nanoporous membranes. Nat. Commun.
7, 13872; 10.1038/ncomms13872 (2016).

Müller, K. et al. Switching Thin Films of Azobenzene-Containing Metal-Organic Frameworks with Visible Light. Chem. Eur. J.
23, 5434–5438; 10.1002/chem.201700989 (2017).

Knebel, A. et al. Azobenzene Guest Molecules as Light-Switchable CO 2 Valves in an Ultrathin UiO-67 Membrane. Chem. Mater.
29, 3111–3117; 10.1021/acs.chemmater.7b00147 (2017).

Tan, N. Y. et al. Investigation of the terahertz vibrational modes of ZIF-8 and ZIF-90 with terahertz time-domain spectroscopy. Chem Commun
51, 16037–16040; 10.1039/c5cc06455d (2015).

Figure 1
Strong Coupling State on Plasmonic Lattice Structures Under Electrochemical Potential Control
Authors: Minamimoto Hiro , Hayashi Takahiro , Murakoshi Kei 
Published: December 2020

The collective oscillation of free electrons in the metal nanostructures induced by the visible light illumination is recognized as the localized surface plasmon (LSP). The coherent light energy exchange between excitons of molecules and LSP can modulate not only the absorption characteristic but also the individual energy decay. This reversible light energy exchange process between LSP and molecular exciton is called as the strong coupling regime. Although the strong coupling can allow use the light energy efficiently, the relative short lifetime of LSP due to the energy dissipation via the radiative damping limits the application. On the other hand, the surface lattice plasmon (SLR) mode which is excited on the two dimensionally arranged metal nanoparticles shows the longer excited lifetime because the diffractive light scattered from each particle is used for the excitation of the LSP at neighboring nanoparticle, resulting in the suppression of the scattering loss. As we demonstrated in our previous study, we have successfully achieved the fine electrochemical structure control method for obtaining the longest lifetime of the SLR mode. From these backgrounds, in this study, we have fabricated the Au lattice structure on a conductive glass and to support organic dye molecules on it to achieve the strong coupling regime. Through the extinction and fluorescence measurements, we have successfully observed the peak splitting which was originated from the formation of the strong coupling. In addition, by the combination of electrochemical method, we have confirmed our successful results for the reversible tuning of the coupling strength. From all experiments, we have successfully estimated the number of the molecules contributing to the strong coupling state.
[1] H. Minamimoto et al., Phys. Chem. C 2018, 122, 14162.