bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystallographically-Oriented Macropores in Multi-Crystalline Zn
Authors: Gerngross Mark-Daniel , Carstensen Jürgen , Adelung Rainer
Published: September 2016

This paper presents the self-organized growth of crystallographically-oriented macropores in multicrystalline Zn sheets by pulsed-potential electrochemical etching in an environmentally friendly aqueous KCl electrolyte. The resulting pores show very high similarity to crystallographically-oriented pores found in III-V semiconductors with respect to branching and intersection of pores. In contrast to pores in other metals like Ti with amorphous TiO2 pore walls, the pore walls in Zn entirely consist of metallic Zn. These pores in multicrystalline Zn are perfectly suitable for mechanical interlocking with polymers since the pores grow under various angles to the sheet surface. All pores grow in <0001> directions with side branching pores in [-12-10] and in [1-210] direction allowing for a good mechanical interlocking to polymers, i.e. they act perfectly as hooks forming a rigid connection between the Zn sheet and the polymer solving the well-known problem of poor adhesion of polymers and paint on Zn surfaces.
(Invited) Preparation of Ordered Anodic Porous Alumina Through-Hole Membrane and Its Applications
Authors: Yanagishita Takashi , Masuda Hideki
Published: September 2016

The preparation of highly ordered anodic porous alumina through-hole membranes by two-layer anodization using concentrated sulfuric acid solution is described in detail. After the formation of a porous alumina layer in an oxalic acid solution, a highly soluble alumina layer was formed at the lower part of the first alumina layer by second anodization in a concentrated sulfuric acid solution. A porous alumina through-hole membrane was then obtained by selective dissolution of the second alumina layer in an appropriate etchant. The residual Al could be reused for the preparation of the ordered anodic porous alumina because an ordered concave array corresponding to the hole arrangement of the detached porous alumina membrane was maintained at the surface of the residual Al even after the etching treatment. The present process allows the high-throughput preparation of ordered anodic porous alumina through-hole membranes.
Synthesis and Magnetic Characterization of (Porous Silicon/"Hard-Soft" Magnetic) Nanocomposites
Authors: Rumpf Klemens , Granitzer Petra , Michor Herwig , Poelt Peter
Published: September 2016

The purpose of this work is to combine magnetic nanostructures of two different metals within porous silicon to influence the magnetic switching behavior of this porous silicon/metal nanocomposite. These “hard/soft” magnetic nanocomposites have been achieved by two different routes. Porous silicon templates in the mesoporous regime have been employed for the electrochemical incorporation of different types of magnetic nanostructures. Two kinds of porous silicon templates have been used, on the one hand double sided porous silicon which has been achieved by etching of an ultrathin wafer in a double tank cell and on the other hand a silicon wafer has been porosified on one side only. The double-sided porous silicon has been filled with Ni on one side and with Co on the other side, also using a double tank cell. In the case of the one-sided sample both metals have been electrochemically deposited alternatingly inside the pores.
Si/SiGe Heterointerfaces in One-, Two-, and Three-Dimensional Nanostructures: Their Effect on SiGe Light Emission
Authors: Lockwood David J , Wu Xiaohua , Baribeau Jean-Marc , Mala Selina A. , Wang Xiaolu , Tsybeskov Leonid
Published: September 2016

The nature of the interfaces between SiGe nanostructures and Si in heterostructures strongly affects carrier mobility and recombination for physical confinement in one, two, and three dimensions. The interface sharpness is influenced by many factors including growth conditions, strain, and thermal processing, which can make it difficult to attain the desired structures. This is certainly the case for nanostructure confinement in one dimension. However, axial Si/Ge nanowire heterojunctions with a Si/Ge nanowire diameter in the range 50–120 nm produce a strong photoluminescence signal associated with band-to-band electron-hole recombination at the nanowire heterojunction that is attributed to a specific interfacial SiGe alloy composition. For three-dimensional confinement, experiments show that two quite different SiGe nanostructures incorporated into a Si0.6Ge0.4 wavy structure exhibit an intense PL signal with a characteristic non-exponential decay time that is remarkably shorter (as much as 1000 times) than that found in conventional Si/SiGe nanostructures.
(Invited) Porous Silicon for Energy Storage at Microscale: Supercapacitors
Authors: Grigoras Kestutis , Keskinen Jari , Grönberg Leif , Ahopelto Jouni , Prunnila Mika
Published: September 2016

Application of porous silicon for energy storage at microscale is discussed, focusing on the electrochemical double layer capacitors (EDLC), commonly called as supercapacitors. Most recent and pioneering achievements in porous silicon based EDLC electrodes are reviewed. Possible ways towards the device integration are shown.
Fe-Based Magnetic Alloy Electrodeposition for Thin Films and Template Based Nanostructures
Authors: Haehnel Veronika , Ma Xiao , Konczak Christoph , Pohl Diana , Uhlemann Margitta , Schlörb Heike
Published: September 2016

The electrochemical fabrication of the Fe-based soft magnetic CoFe alloy and the shape memory active Fe-Pd alloy is reported. We examine the influence of electrolyte composition and deposition regime or post treatment on morphology, composition and structural development of the deposits. Up to 10 µm thick CoFe films with 55 at.% Fe were achieved from simple and additive adjusted electrolytes by potentiostatic or alternating potential deposition regime. Micropatterned deposits of smooth surface morphology and high saturation magnetization applicable as magnetic field gradient generator can be prepared best by the combination of SDS additive and alternating potential regime. The Fe-Pd alloy has been deposited and heat treated to achieve a composition with 30 at.% Pd and to adjust the crystal structure. For thin films and nanowires the transition from bcc to fcc phase is accomplished. This represents a good starting point towards shape memory active materials and their further physical characterization.
Superconformal Bottom-up Cobalt Deposition in High Aspect Ratio through Silicon Vias
Authors: Josell Daniel , Silva Manoj , Moffat Thomas P.
Published: September 2016

This work demonstrates void-free cobalt filling of 56 mm tall, annular Through Silicon Vias (TSVs) using a mechanism that couples suppression breakdown and surface topography to achieve controlled bottom-up deposition. The chemistry, a Watts electrolyte containing a dilute suppressing additive, and processes are described. This work extends understanding and application of the additive-derived S-shaped Negative Differential Resistance (S-NDR) mechanism, including previous demonstrations of superconformal filling of TSVs with nickel, copper, zinc and gold.
Effect of Annealing Temperature on the Coercivity and the Electrical Resistivity of the Electroplated Ni-Fe-W Alloy Film
Authors: Mundotiya Brij Mohan , Rissing Lutz , Wurz Marc Christopher
Published: September 2016

80Ni-17Fe-3W alloy films are electroplated on Si wafer. The as-plated film is smoothed and annealed at different substrate temperature values of 200 °C, 300 °C, 400 °C, and 500 °C. The atomic force microscopy results show that the roughness of the as-plated alloy film increases with an increase in the annealing temperature. It is found that an increase in the annealing temperature, the coercivity increases while the electrical resistivity decreases. The plated alloy film annealed at 500 °C has the highest coercivity of 383 A/m and the lowest resistivity of 25 µohm-cm. The coercivity and electrical resistivity of the samples are measured with the help of a BH-Looper and four-point probe techniques, respectively.
(Invited) Characterization of Interface Defects by the Charge Pumping Technique
Authors: Tsuchiya Toshiaki
Published: September 2016

Charge pumping (CP) technique is known to be a highly-precise method for evaluating the density of interface traps (defects) between the gate oxide and the semiconductor surface in MOSFETs. Recently, we have developed procedures to detect and characterize single MOS interface traps by the CP method, and found that two energy levels participate in electron capture/emission processes in a single trap, and clarified that the CP current per trap shows various values in the range of 0~2fq, but not a fixed value of fq (f: the gate pulse frequency, q: the electron charge). This results from the differences in the pairs of donor-like and acceptor-like trap energy levels. Besides the MOS interface, we have successfully evaluated the density of the interface defects in a SiGe/Si heterostructure introduced into the channel region of Si MOSFETs using a low-temperature CP method, avoiding interference from the interface traps between the gate oxide and the semiconductor surface.
(Invited) DLTS Studies of Defects in n-GaN
Authors: Tokuda Yutaka
Published: September 2016

We have studied electron and hole traps in Si-doped n-GaN grown by metal organic chemical vapor deposition on n+-GaN, sapphire, SiC and Si substrates. DLTS using bias pulses, MCTS using above-band-gap light pulses and ODLTS using below-band-gap light pulses have been employed for fabricated Schottky diodes. The energy levels and capture cross sections of four electron traps and three hole traps are reported. A variation of dominant traps in concentration between wafers and among diodes on each wafer is observed, which is discussed based on the dependence of trap concentrations on the growth conditions.
(Invited) Current Stage of the Investigation of the Composition of Oxygen Precipitates in Czochralski Silicon Wafers
Authors: Kot Dawid , Kissinger Gudrun , Schubert Markus Andreas , Sattler Andreas
Published: September 2016

In this work, we look on the current stage of the investigation of the composition of oxygen precipitates obtained with the help of different techniques. Moreover, we present our recent and new investigation of the composition of oxygen precipitates carried out by means of energy dispersive X-ray spectroscopy, electron energy loss spectroscopy, and Fourier transform infrared spectroscopy. The FTIR spectra measured at liquid helium temperature are compared with the spectra simulated on the basis of experimental results obtained by scanning transmission electron microscopy. According to the results obtained by all methods the precipitated phase of plate-like as well as octahedral precipitates is close to SiO2.
Combined Effect of Rapid Thermal Annealing and Crystal Nature on the Gate Oxide Reliability of Czochralski Silicon
Authors: Shin Jung-Won , Lee Woo-Sung , Kim Ja-Young , Lee Anselmo Jaehyeong , Kang Hee-Bog , Lee Sung-Wook
Published: September 2016

The effect of RTA treatment on the gate oxide reliability in the manner of as-grown and RTA-induced defect state was investigated. The RTA pre-treatment brings significant degradation of GOI yield, and the effect becomes severe as the v/G of a sample is increased. On the other hand, GOI yield was recovered when successive CMP processes was applied on the wafer after finishing the RTA process. In summary, void-rich layer with a thickness of few micrometers was formed in the wafer surface after the RTA treatment, and the density of void is clearly affected by the as-grown vacancy concentration.
Investigation of the Composition of the Si/SiO2 Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS
Authors: Kissinger Gudrun , Schubert Markus Andreas , Kot Dawid , Grabolla Thomas
Published: September 2016

We investigated thermal oxide layers of different thickness on (100) and (111) silicon substrates by STEM/EELS in order to determine the stoichiometry profiles and compared these with stoichiometry profiles of plate-like and octahedral oxide precipitates in silicon. The results of these investigations demonstrate that the stoichiometry of SiO2 (x=2) cannot be reached if the oxide layer thickness is lower than 10 nm for thermal oxides grown at 900 °C. The lower the thickness of the layer is the lower is the maximum x value. This is due to an interface layer of equal maximum slope for all oxide layers. The slope was obtained from fitting by sigmoid functions. Similar results were found for the oxide precipitates in silicon but the slope is somewhat lower.
Depth Profile Analysis of Metals Gettered By Bulk Micro-Defects (BMDs) in Silicon Substrates
Authors: Saga Koichiro , Ohno Rikiichi
Published: September 2016

We have experimentally demonstrated the depth profiles of metals gettered by BMDs in silicon wafers with different densities and sizes of BMDs. It has been found that although the total surface area of the BMDs per unit volume is dispersed uniformly through the wafers or slightly increases with increasing depth below the denuded zone (DZ), more metals are gettered at around the depth where the total surface area of the BMDs sharply increases just below the DZ. It is considered that metals diffused in the DZ are gettered by BMDs near the DZ during cooling, while metals diffused in the deeper regions are dispersedly gettered by each BMD in deeper regions during cooling.
(Invited) Defect Evolution during Silicon Smartcut™
Authors: Rieutord François , Tardif Samuel , Mazen Frédéric , Landru Didier , Kononchuk Oleg
Published: September 2016

We describe here the sequence of evolution of defects after hydrogen alone or hydrogen plus helium implantation in silicon, from matrix incorporation up to microcracks formation. We detail the different steps of the process, concentrating on experimental results from X-ray scattering and IR microscopy observations
(Invited) Silicon Nanowires: Donors, Surfaces and Interface Defects
Authors: Fanciulli Marco , Paleari Stefano , Belli Matteo , Lamperti Alessio
Published: September 2016

In the present work we focus on the investigation by electron spin resonance (EPR) and complementary techniques (such as SEM, ToF-SIMS, XPS) of silicon nanowires produced by metal-assisted chemical etching (MACE). In particular we will report on the impact of the MACE process on the donors (P and As) and on surface passivation processes based on H or S. The efficiency of the passivation processes has been monitored by following the EPR signals of the Pb centers at the Si/SiO2 interface.
Low Temperature Effect on Strained and Relaxed Ge pFinFETs STI Last Processes
Authors: Oliveira Alberto Vinícius de , Simoen Eddy , Agopian Paula Ghedini Der , Martino Joao Antonio , Mitard Jerome , Witters Liesbeth , Langer Robert , Collaert Nadine , Thean Aaron , Claeys Cor
Published: September 2016

Ge pFinFETs, fabricated either with an STI last process on a Ge-on-Si virtual substrates or a SiGe strain-relaxed buffer, have been systematically evaluated at temperatures from 200 K down to 77 K. In the first cases, the Ge channel is relaxed, while in the second case, compressively strained fins have been obtained. Cryogenic testing shows to be an important tool for evaluating the static device performance parameters and it helps to resolve the impact of strain on the drain current. Apart from that, the off-state leakage in the subthreshold region can be evaluated as a function of temperature, showing that besides thermal Shockley-Read-Hall generation, other field-assisted mechanisms play a role.
(Invited) On the Manipulation of Phosphorus Diffusion as Well as the Reduction of Specific Contact Resistivity in Ge by Carbon Co-Doping
Authors: Luo Jun , Liu Jinbiao , Simoen Eddy , Wang Guilei , Mao Shujuan , Radamson Henry H , Duan Ningyuan , Li Junfeng , Wang Wenwu , Chen Dapeng , Zhao Chao , Ye Tianchun
Published: September 2016

In this work, the manipulation of phosphorus diffusion as well as the reduction of the specific contact resistivity in Ge by carbon co-doping is explored. It is found that there is an optimum condition for carbon implantation to suppress the rapid P diffusion effectively. For such a condition, the implanted carbon sits at the half range of the pre-amorphized Ge layer. In this case, both the diffusion of P in the amorphous layer and in the Ge virtual substrate beyond the amorphous/crystal (a/c) interface can be effectively manipulated. Except the control of P diffusion, the specific contact resistivity (ρc) between as-formed NiGe and the Ge substrate in the presence of C can be also reduced, compared with the reference without C. At 500°C germanidation temperature,the ρc values are reduced from 1.1x10-4 Ω-cm2 and 2.9x10-5 Ω-cm2 for NiGe/n- and p-Ge contacts without carbon to 7.3x10-5 Ω-cm2 and 1.4x10-5 Ω-cm2 for their counterparts with carbon, respectively.
(Invited) Significant Reduction of Leakage Currents in Reverse-Biased Ge n+/p Junctions by Taking Care of Peripheral Passivation Layer
Authors: Liu Chi , Ikegaya Hiroki , Nishimura Tomonori , Toriumi Akira
Published: September 2016

We discuss the leakage current mechanism in Ge n+/p junctions. We investigated effects of the passivation layer surrounding the contact area in planar type n+/p junctions on the reverse-biased leakage current, and found more than 6-orders of magnitude difference in the on/off ratio at V=|1| V. It is, to our knowledge, the highest on/off ratio in the conventional planar n+/p junctions.
Conductive AFM Topography of Intrinsic Conductivity Variations in Silica Based Dielectrics for Memory Applications
Authors: Buckwell Mark , Zarudnyi Konstantin , Montesi Luca , Ng Wing Hung , Hudziak Stephen , Mehonic Adnan , Kenyon Anthony Joseph
Published: September 2016

As flash memory approaches its scaling limit, resistive RAM devices show promise for next generation memories due to their small size and low operating voltages enabling denser packing and lower power consumption. Many materials have shown desirable active layer properties, yet silicon based memories are particularly appealing as they allow for facile integration into CMOS infrastructures. Our devices are composed of silicon suboxide sandwiched between conductive electrodes. Here, we present results probing the three-dimensional structure of conducting pathways following the application of an electric field. These pathways, or filaments, give dielectric materials memory functionality yet are difficult to image with conventional techniques owing to low imaging contrast. Our results highlight the importance of conductive atomic force microscopy for three-dimensional analyses and show that filamentation conforms to the pristine dielectric structure. We also present findings showing that multiple growths can compete during the filament growth process.
(Invited) Physical Models of Program and Read Fluctuations in Metal Oxide Resistive RAM
Authors: Ielmini Daniele
Published: September 2016

The explosive growth of digital data poses increasing demand for novel hardware capable of storing, searching, and analyzing large amounts of data with high efficiency and low power consumption. In this context, resistive switching memories (RRAM) are under scrutiny for storage-class memories and in-memory computing to alleviate or even suppress the von Neumann bottleneck between memory and the central processing unit (CPU). RRAM devices provide an ideal solution to solve this dilemma, thanks to their high speed, low power, 3D integration and scalability. However, fundamental issues of switching variability and resistance stability must be understood and solved for a mature RRAM technology. This work addresses program and read variability in RRAM, presenting an overview of physical models to describe and predict statistical variations and their impact on device reliability.
A Method for Effective Work Function Monitoring
Authors: Marinskiy Dmitriy , Loy Thye Chong , Edelman Piotr , Lagowski Jacek
Published: September 2016

Monitoring of the effective work function (EWF) is proposed that involves quantification of the flatband voltage early during metal gate fabrication process by a non-contact micro corona-Kelvin, enabling faster feedback than traditional MOS capacitor based measurements. Two key elements are: 1. corona charging and 2. Kelvin probe force microscopy, KPFM. The surface voltage decay after corona charging is measured with KPFM under modulated light enabling parameter free extraction of the flatband voltage, VFB and EWF. Results for n- and p-type metals show excellent correlation with end of line CV measurements. The micro corona-Kelvin method allows quantification of two more EWF sensitive parameters: silicon surface potential barrier and the tunneling barrier at the metal / high-k dielectric interface. Results for n- and p-type metals are consistent with the expected behavior.
Mechanical/Structural Properties of the Key Thin Film Materials Ag, Cu, & Ni for Electronics Applications
Authors: Mohammed Yousuf , Josell Daniel , Baumgart Helmut , Elmustafa A A
Published: September 2016

Metallic films of Ag, Cu, and Ni each of 150, 300, 600 and 1000 nm thick were deposited on Si using E-beam evaporation deposition technique. A shutter was used to successively cover increments of 1² of the wafer at a time, starting with the wafer fully uncovered. A thin titanium layer of 10 nm is first deposited over the entire Si wafers followed by 150, 300, 600, and 1000 nm of the 2² target material. Vacuum conditions at the start were ~1x10-7 torr and reached as high as 2x10-6 torr during the copper deposition due to outgassing. The structural and surface properties were explored using field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The nanomechanical properties were measured using nanoindentation to determine the modulus and hardness of the Ag, Cu, and Ni films. Nanocrystalline grain structure formation is observed to dominate the crystal film growth. The hardness increases as the film thickness decreases and remains nearly flat for the same film with depth except for the very thin films as they suffer what is known as tapping effect.
(Invited) Large Mobility Modulation Due to Discrete Impurities in Nanowires
Authors: Sano Nobuyuki
Published: September 2016

The impurity-limited resistance in quasi-one dimensional nanowire structures is studied under the framework of the Landauer and the Lippmann-Schwinger theories. The charge polarity dependence of the impurity-limited resistance (mobility) under localized impurities with short-range scattering potential is theoretically clarified. We show that the impurity-limited resistance (mobility) could be modulated over three orders of magnitude by varying the axial separation of the ionized impurities, provided that the charge polarity of the impurities is opposite to that of carriers. The present results are consistent with recent experimental observations that the electron mobility in Junctionless-FETs is enhanced as the donor concentration becomes large, contrary to the usual trends found from the semi-classical calculations.
(Invited) Electrochemical Gating-Induced Hydrogenation in VO2 Nanowires at Room Temperature
Authors: Kanki Teruo , Sasaki Tusbasa , Tanaka Hidekazu
Published: September 2016

Reversible and memristive modulation of the transport properties in vanadium dioxide (VO2) nanowires by electric field-induced hydrogenation at room temperature was demonstrated using the nanogaps separated by humid air in field-effect transistors with planer-type gates (PG-FET). These PG-FETs allowed us to directly investigate behavior of revealed hydrogen intercalation and migration aspects with time and spatial evolutions in nanowires. These results show that air nanogaps can operate as an electrochemical reaction field, even in a gaseous atmosphere, and offer a new technique to introduce reversible redox reactions even at room temperature and will serve as a powerful tool for examining the transport properties of the redox effect.
(Invited) Mechanism of Low Temperature ALD of Al2O3 on Graphene Terraces
Authors: Kwak Iljo , Park Jun Hong , Grissom Larry , Fruhberger Bernd , Kummel Andrew
Published: September 2016

Uniform and defect-free Al2O3 films were grown on highly oriented pyrolytic graphite (HOPG) terraces by thermal atomic layer deposition (ALD) at low temperature (50 oC) without any functionalization of the surface. Controlling the pulse times of trimethylaluminum (TMA) and H2O while using short Ar purge times, 1-2 nanometer size Al2O3 particles were formed on the HOPG terraces. The particles provided a layer of nanoscale nucleation centers on the HOPG terraces. Capacitance-voltage measurements of Al2O3 films grown at 50 oC using 50 ALD cycles showed an areal capacitance 1.17 mF/cm2 with very small frequency dispersion, consistent with the absence of induction cycles and formation of a high quality interface. The leakage current of the Al2O3 was ~10-5 A/cm2 in large area devices (1900 mm2) which is comparable with results from devices prepared using an identical ALD process for Al2O3 on Si0.7Ge0.3(001) substrates, and is consistent with the absence of pinholes.
(Invited) Evaluation of Few-Layer MoS2 Transistors with a Top Gate and HfO2 Dielectric
Authors: Young Chadwin D , Zhao Peng , Bolshakov-Barrett Pavel , Azcatl Angelica , Hurley P. K. , Gomeniuk Y. Y. , Schmidt Michael , Hinkle Christopher L , Wallace Robert M
Published: September 2016

Top-gated, few-layer MoS2 transistors with a HfO2 gate dielectric are fabricated and subsequently characterized. Both transistor performance and gate-stack interface quality were characterized with current – voltage (I-V) and capacitance – voltage (C-V) measurements. The interface state density (Dit) was extracted and analyzed. The importance of annealing before high-k deposition to reduce the leakage current of the HfO2 gate oxide was shown. Finally, we show preliminary data of HfO2 on MoSe2 to show the possibility of extending this top-gate approach to other TMDs.
(Invited) Xenes: A New Emerging Two-Dimensional Materials Platform for Nanoelectronics
Authors: Molle Alessandro
Published: September 2016

The recent discoveries of silicene, germanene, and stanene, commonly denoted as Xenes (with X being Si, Ge, Sn), and their ligand-functionalized “Xane” derivatives, brings to the forefront an important class of two-dimensional (2D) elementary crystals. Similar to graphene, these materials are comprised of group IV atoms arranged in a honeycomb lattice, but with varying degrees of buckling that inherently stem from the interplay of sp2 and sp3 hybrid bonds. So far, Xenes were synthesized as epitaxially grown monolayers on substrates. An overview of the state-of-the-art on the Xenes-on-substrates will be here given. The silicene-on-silver will be taken as a representative example of the Xenes. Generally, two aspects qualify the epitaxy of Xenes on substrates, the emergence of a vertically buckled lattice and the strong interaction with the hosting substrate. The former fact may offer a potential to access to (and control of) the quantum spin Hall state in Xenes. This perspective is highly appealing as a new paradigm shift in nanoelectronics, and it will be briefly outlined. The latter fact is currently limiting an easy exploitation of Xene for functional applications and device integration. As a viable solution, the delamination of an encapsulated silicene monolayer will be presented as operative process for the fabrication of a silicene transistor that can be universally extended to other epitaxial Xenes.
Studies of Parylene C Microfibrous Thin Films Electrical Properties
Authors: Khawaji Ibrahim H , Awadelkarim Osama O. , Lakhtakia Akhlesh
Published: September 2016

We have fabricated and measured the room-temperature capacitance in metal-insulator-metal (MIM) structures utilizing the Parylene C films as the insulators in the frequency range 1 kHz to 1 MHz. The Parylene-C films were of variable thicknesses and were either spin-on dense films or columnar microfibrous thin films (μFTFs) grown using oblique angle physicochemical vapor deposition. The values of the vapor tilt angle, χv, used were 30°, 60°, or 90°. Expectedly, columnar microfibrous thin film of Parylene C is observed to have lower values of k than the dense one. However, it is observed that the dielectric constant of the μFTFs is increased with increasing deposition tilt angle χv. This is explained in terms of film porosity as a function of χv, which is enhanced in films deposited at lower tilt angles. The dependence of k on measurement frequency suggests that molecular dipole effects dominate charge polarization in the films.
Selective-Area Growth of Vertical InGaAs Nanowires on Ge for Transistor Applications
Authors: Yoshida Akinobu , Tomioka Katsuhiro , Ishizaka Fumiya , Chiba Kohei , Motohisa Junichi
Published: September 2016

III-V compound semiconductors and Ge are promising future channel materials because of their high carrier mobility. For example the electron mobility of InAs is about 20 times faster than that of Si at room temperature and hole mobility of Ge is about 5 times faster than that of Si. In this paper, we report direct integration of InGaAs nanowires (NWs) on Ge(111) substrate by selective-area metal organic vapor phase epitaxy (SA-MOVPE) for realization of high carrier mobility InGaAs/Ge hybrid CMOS applications, and characterization of the composition and growth modes of InGaAs NWs by X-ray diffraction (XRD) measurement.
Temperature-Dependent and Dielectric Relaxation of Porous Silicon Prepared by Electrochemical Etching
Authors: Fonthal Rico Faruk , Oliveros Edward Steven , Chavarria Mario
Published: September 2016

In the electronic devices based on porous silicon (PS) is important understand the physical mechanisms governing the electrical behaviour in the PS/c-Si structure. In order to investigate the conduction mechanisms in the PS/p-Si heterojunction, we prepared the PS by electrochemical etching. The temperature dependence of the porous silicon was studied in the range from 300 K to 393 K, in a range until 10 V. On the other hand, the AC electrical measurements were performed from 5 Hz to 107 Hz. The calculated activation energies were close to 0,42 eV at 2 V. The physical mechanisms involved in the Au/porous silicon contacts and porous silicon/p-Si interface can be obtained from the voltage dependence of the fitting parameters according to electrical model circuits in DC and AC. We found the dielectric behavior of the sample; the relaxation region is presented at high frequency
Structure of Pr Oxide Films on Si Deposited by Reactive Sputtering
Authors: Kumagai Kenta , Yamaguchi Kouta , Hara Kenta , Suzuki Setsu , Ishibashi Keiji , Yamamoto Yasuhiro
Published: September 2016

Praseodymium oxide thin films were fabricated on p-type Si (100) substrates by reactive RF magnetron sputtering with a metal Pr target in Ar + 10 % O2. Deposited films were post-annealed in a nitrogen ambient for 30 minutes at 300, 500 and 800 °C. The XRD measurement revealed that the as-deposited Pr oxide film was crystalized and the dominant diffraction line of cubic PrO2 was maintained up to 500 °C. After annealing at 800 °C, the new diffraction line indicating the phase transition to hexagonal Pr2O3 appeared. The TEM observation revealed that the SiO2 layer present at the interface between the film and the Si substrate in the as-deposited sample was scavenged during the post-annealing up to 500 °C. After annealing at 800 °C, the Pr oxide film had the three-layered structure: the columnar crystal layer, the crystalline grain layer, and the amorphous silicate layer from the surface.
(Invited) Control of Atomic Layer Reactions in Plasma Processing
Authors: Ventzek Peter , Sherpa S D , Wang M , Rastogi V , Ranjan Alok
Published: September 2016

Control of atomic layer reactions in discrete adsorption and desorption steps is what enables atomic layer etching (ALE) and escape of process trade-offs for 7 nm technologies and beyond. Silicon ALE has been demonstrated but challenges remain mating precursors, process chambers and materials in ALE for other materials. This brief paper reviews recent activity devoted to the engineering of silicon, oxide and nitride material ALE. Hybridized ALD-ALE and ALD-Etch processes are discussed which may overcome the challenges posed by the etch of oxide and nitride materials for patterning, contact and memory applications.
Plasma-Enhanced Atomic Layer Deposition of Iron and Titanium Phosphates as Electrode Materials for 3D-Structured Lithium-Ion Microbatteries
Authors: Dobbelaere Thomas , Mattelaer Felix , Dendooven Jolien , Vereecken Philippe M. , Detavernier Christophe
Published: September 2016

Using novel PE-ALD processes based on exposures to trimethyl phosphate (TMP) plasma, O2 plasma, and a metal precursor, thin films of either iron phosphate or titanium phosphate were deposited using either tert-butylferrocene as the iron precursor or titanium isopropoxide as the titanium precursor. Both processes worked optimally at substrate temperatures of 300 °C, where in both cases linear and self-limiting growth was observed with unusually high growth rates of 1.1 nm/cycle (for iron phosphate) and 0.66 nm/cycle (for titanium phosphate). The as-deposited films were amorphous. They could be used as lithium-ion battery electrodes after electrochemical lithiation, showing activity around 3.1V (iron phosphate) and 2.7V (titanium phosphate) relative to Li/Li+. By depositing the films on 3D-structured micropillar substrates rather than planar ones, the footprint-normalized capacity could be increased by more than a factor of 15.
(Invited) Template Assisted Synthesis of Porous Metal Oxide and Metal Nanostructures by ALD
Authors: Deng Shaoren , Kurttepeli Mert , Bals Sara , Cott Daire J. , Detavernier Christophe
Published: September 2016

Porous materials are widely used in various applications since they can provide tremendous active surface area, e.g. in catalysis, energy storage, absorption and detection of toxic materials, etc. In recent years, due to its superior advantage in conformally coating porous materials, the ALD technique attracted great attention and has been used to synthesize nanomaterials with porous features. Templates are indispensable for these ALD-based approaches, since ALD can only deposit 2D thin film instead of 3D porous structures. In this paper, we will give a thorough review on the existing literature reported on template assisted and ALD based synthesises of porous nanomaterials of metal oxides and metals. The dis/advantages of each kind of template will be surveyed.
A Rotation Fluidization Coupled Atomic Layer Deposition Reactor for Nanoparticle Coating
Authors: Duan Chen-Long , Chen Rong
Published: September 2016

Atomic layer deposition (ALD) is an attractive approach for precisely controllable and conformal coating on nanoparticles (NPs). Compared with flat substrates, NPs have very large specific surface area, form agglomerate and stack together during deposition. Therefore, special reactor and process are needed to promote the precursor diffusion for uniform deposition and efficient process. In this paper, an ALD reactor is introduced which uses fluidization to facilitate precursor transport and couples rotation to intensify the dynamic dismantling of soft-agglomerates, exposing individual particle to precursors. In situ mass spectrometry monitoring of the reaction shows nearly 100% precursor utilization with proper deposition process. The linear relationship of statistical element mass concentrations with deposition cycles demonstrates the precise controllability. The microscale morphology of the Al2O3 coated SiO2, Fe3O4, CeO2 and AlH3 NPs shows the uniformity and conformity of the films on individual particles, which reveals the generosity of the reactor on various nanostructures.
(Invited) Using Inherent Substrate-Dependent Nucleation to Promote Metal and Metal Oxide Selective-Area Atomic Layer Deposition
Authors: Parsons Gregory N. , Kalanyan Berç , Atanasov Sarah E. , Lemaire Paul , Oldham Chris
Published: September 2016

We report studies of thin film metal and metal oxide nucleation during ALD to promote native substrate bias and improve selectivity. Tungsten ALD using WF6/SiH4 onto SiO2 proceeds when surface Si-H begins to form, allowing WF6 reduction to W and elimination of SiF4. In-situ analysis indicates that initial nucleation reactions can be impeded on SiO2 by introducing reactants that help passivate active surface sites. Moreover, eliminating water during TiO2 ALD slows metal substrate oxidation to promote nucleation delay.
(Invited) Atomic Layer Deposition for Catalyst “Bottom-up” Synthesis
Authors: Lu Junling
Published: September 2016

Atomic layer deposition (ALD) has appeared as a new promising method of design and synthesis of supported catalysts. The nature of self-limiting surface reactions of ALD makes possible to precisely “bottom-up” construct catalytic materials on high-surface-area supports with well-defined structures in a cyclic manner. This provides insights for fundamental understanding of reaction mechanisms and structure-activity relations, and facilitates rational design of advanced catalysts with high performance. Here we summarize our recent attempts to synthesize supported metal catalysts using ALD. The capability of achieving precise control over the particle size, structure and composition metal nanoparticles is emphasized. In addition, applying metal oxide ALD onto metal nanoparticles to tailor the catalytic performance of metal catalysts including activity, selectivity and stability are also discussed.
A Precise and Scalable Post-Modification of Mesoporous Metal-Organic Framework NU-1000 Via Atomic Layer Deposition
Authors: Kim In Soo , Farha Omar K. , Hupp Joseph T. , Gagliardi Laura , Chapman Karena W , Cramer Chris , Martinson Alex B. F.
Published: September 2016

The connectivity of NU-1000, a metal-organic framework, gives rise to Zr6 nodes with hydroxyl-containing functional groups pointing into the large 1D mesoporous hexagonal channels of the framework. These free and exposed –OH groups are ideal grafting sites, and they can be easily tailored to serve a specific function. Through atomic layer deposition in MOFs (AIM), we demonstrate the ability to form several oxides with atomic precision at the exposed –OH sites of NU-1000. Importantly, this process occurs without changing the overall structure of the framework. Recent progress in scaling AIM process of the ultrahigh surface area (2300 m2/g) framework as well as progress in pinpointing the location and mechanism of surface chemical reactions of catalytically relevant metals is discussed. Computational, synchrotron, and in-situ analytical methods including DFT, differential electron diffraction, and in situ FTIR are brought to bear on several new metal systems, many of which show remarkably self-limiting behavior.
Low Temperature Atomic Layer Deposited TiO2 Compact Layers for Planar Perovskite Solar Cells
Authors: Kim In Soo , Haasch Richard , Cao Duyen , Farha Omar K. , Hupp Joseph T. , Kanatzidis Mercouri , Martinson Alex B. F.
Published: September 2016

Titanium dioxide (TiO2) thin films have been utilized in a wide range of applications in optoelectronics and solar energy conversion. In particular, TiO2 has been exclusively used in photovoltaic devices and photoelectrochemical cells owing to its ability to efficiently transport electrons and passivate photoactive materials against aqueous media. However, TiO2 exhibits optimal transport properties in the crystalline anatase phase, and thus requires a high temperature annealing, which significantly limits its application in temperature sensitive substrates or active materials (e.g. organic-inorganic hybrid perovskites). Moreover, while high resistance of TiO2 films necessitates the need for ultrathin films to reduce series resistance in PV devices, the synthesis of ultrathin pinhole-free TiO2 films remains a challenge through conventional deposition methods. To address these issues, TiO2 compact layers for planar perovskite PV devices were deposited via atomic layer deposition (ALD) – a chemically diverse vapor phase deposition technique with the capability to synthesize ultrathin pinhole-free films.
In-situ Monitoring System Equipped with FT-IR and QMS and Thermal Decomposition of Zr(NCH3C2H5)4 Precursor
Authors: Park In-Sung , Seong Sejong , Jung Yongchan , Lee Taehoon , Ahn Jin-Ho , An Jong-Ki , Yun Juyoung
Published: September 2016

An in-situ monitoring system equipped with both fourier transform infrared (FT-IR) spectroscopy and quadrupole mass spectroscopy (QMS) was introduced and measured the decomposition of Zr(NCH3C2H5)4 precursor, which usually used in ALD of ZrO2 films. For the actual influence of the decomposition state of the metalorganic precursor on the properties of the produced film, Zr(NCH3C2H5)4 precursor was heated in the temperature ranges from 100 °C to 200 °C by the step of 25 °C. As a decomposed reference, the acquisition FT-IR and QMS data at 500 °C was used and compared with those at lower temperature. The increase of IR peak at 2962 cm-1 due to C-H in CH3 ligands and the generation of peak at 711 cm-1 due to N-H bonds were useful to monitor the decomposition of Zr(NCH3C2H5)4, where the latter stated to appear from 125 °C, indicating the onset temperature of decomposition.
Tuning the Performance of Pt/HfO2/Ti/Pt ReRAM Devices Obtained from Plasma-Enhanced Atomic Layer Deposition for HfO2 Thin Films
Authors: Hardtdegen Alexander , Zhang Hehe , Hoffmann-Eifert Susanne
Published: September 2016

Ultrathin, dense, high purity, stoichiometric HfO2 films were grown by plasma-enhanced atomic layer deposition from TEMAH and O2 plasma at a substrate temperature of 300°C. Utilizing these high quality HfO2 thin films of precise thickness enabled an accurate study of the effect of the thickness of the oxide, i.e., 5 nm and 8 nm HfO2, and the oxygen exchange layer (OEL), i.e., 5 nm and 10 nm Ti, on the electroforming and resistive switching performance. A thinner oxide layer and a thicker OEL, respectively, resulted in a reduction of the electroforming voltage due to an easier formation of the conductive filament. In addition, differences in the bipolar type resistive switching behavior of various HfO2/Ti cells were observed and a transition into complementary switching was found for the stack built with 8 nm HfO2 and 5 nm Ti.
(Invited) Semiconductor Packaging Technology to Progress the IoT Era
Authors: Takeno Yasuhiko
Published: September 2016

AI (Artificial Intelligence) and IoT that many things on the Internet to connect (Internet of Things) technology is going to bring about the economic boom changing the industry and human life. Semiconductor market, has expanded the market while repeating the ups and downs of the economy, Semiconductor market at that time is expected to increase 30 percent from 2015, of which about 70% is in the IOT. Package has been changed to suit the application equipment. And packaging technology required for the IoT era is a SiP of 2D, 2.5D, 3D. In the Edge side, is used package technology called FOWLP, AI chip package in the data center side, 3D stacked DRAM (HBM, HMC) and is connected to the GPU and CPU in 3D and 2.5D, further new high-density, high-speed packaging technology is required.
A Novel Bottom up Fill Mechanism for the Metallization of Advanced Node Copper Interconnects
Authors: Mevellec Vincent , Thiam Mikailou , Suhr Dominique , Religieux Laurianne , Blondeau Paul , Chaumont Jean-Baptiste , Raynal Frederic
Published: September 2016

A new alkaline copper plating bath enabling a unique and innovative bottom up effect for advanced damascene and dual damascene interconnect metallization is described. The formation of an ultra-stable polynuclear copper(I) complex during the early stage of the deposition process inhibits copper reduction, leading to a very strong suppressing effect. Bottom up growth is then achieved by means of selective breakdown of the suppressing layer from the bottom to the top of the features without any accelerator additive.
The Suppression Induced S-NDR Mechanism for Defect-Free Filling of High Aspect Ratio Features
Authors: Josell Daniel , Moffat Thomas P.
Published: September 2016

Superconformal electrodeposition in Through Silicon Vias for multiple metal systems is summarized and explained using models based on suppressor-induced, S-shaped negative differential resistance (S-NDR). Recent results for Ni are detailed, and the filling morphology is compared to previously published observations of superconformal Au, Cu and Zn in TSVs. Voltammetric measurements for quantifying the kinetics and interactions of metal deposition and suppressor adsorption are shown. Dependence of the superconformal filling behavior on deposition conditions including suppressor concentration, transport and deposition potential are described. S-NDR models based on fractional coverage of adsorbed suppressor capture experimental trends and predict the filling geometries. The results demonstrate the generality of the S-NDR mechanism for achieving void-free filling of large features by electrodeposition and the power of S-NDR based models for prediction of filling evolution and process design.
Electroplating through Fluidic Channels as Production Technology for 3D Interconnect Devices and Sensing Structures
Authors: Rechel Mathias , Bengsch Sebastian , Wurz Marc Christopher
Published: September 2016

Electroplating is a common process in micro technologies and in large scale application to create e.g. corrosion protected surfaces (1). New technologies as three dimensional printing and vacuum casting enable new methods to create surfaces. This provides the opportunity to merge micro structures [e.g. conductors] with macro structures [e.g. curvature].The created textures might be implemented in an electroplating based pattern transfer process. The results indicate the possibility of creating functional planar and three dimensional structures using the described technology.
Copper Oxide Direct Bonding of 200mm CMOS Wafers with Five Metal Levels and TSVs: Morphological and Electrical Characterization
Authors: Cavaco Celso , Peng Lan , Lavizzari Simone , Claes Jesse , Hoovels Nele V. , Guerrieri Stefano , Tezcan Deniz Sabuncuoglu , Osman Haris
Published: September 2016

We report for the first time complete data on 200mm wafer to wafer aligned copper oxide direct bonding of wafers with five metal levels each with through-silicon-vias (TSVs) as backside connection. Both surface acoustic microscope (SAM) and cross-section scanning electron microscope (X-SEM) images taken across the bonded wafer pairs evidence the good bonding quality of the resulting interface. Kelvin structures and daisy chains with up to 2500 copper to copper bonded pads are shown to be connected successfully and its resistance value to match a target value.
(Invited) Variability and Performance on FDSOI Technology with Strained SSOI Substrate and SiGe Channel
Authors: Mazurier Jérôme
Published: September 2016

Fully Depleted SOI (FDSOI) technology has been introduced at the 28nm node as a low-cost alternative strategy to FinFET. Developments on-going on 22nm and 14nm demonstrates the interest of this technology for CMOS scaling. In this talk, mismatch on FDSOI technology will be presented in order to list the main contributors of local variability. Back-bias impact on electrical parameters and variability will be discussed. Then, the effect of strain boosters on device variability and performance will be presented, including strained SOI substrates (sSOI), SiGe S/D and compressive/tensile CESL layer.