bluuebunny/crossref_metadata_2025 huggingface dataset:
Epitaxial Growth and Layer Transfer of InP through Electrochemically Etched and Annealed Porous Buried Layers
Authors: Chen Douglas , Kou Xiaolu , Sareminaeini Sahar , Goorsky M. S.
Published: September 2014

High crystalline quality InP is epitaxially grown on porous InP layers and characterized. Etching the wafers in hydrochloric acid with different concentrations and current densities create a dual layer porous structure with a more dense top layer for epitaxial growth and a buried porous layer. Annealing the structure forms voids in the buried layer. Epitaxial layers with thickness of about 2 µm were grown on dense layers. The layers grown were analyzed by transmission electron microscopy and high resolution x-ray diffraction and determined to be high quality single crystal layers. The porous samples created were bonded to PDMS substrates and the top layer was easily peeled off due to fracture through the high porosity layer. Layer transfer was also performed by gluing the samples to glass slides and pulling them apart. The transferred layers were characterized by scanning electron microscopy. These results point to the usefulness of porous III-V layers as templates for epitaxial growth and device transfer.
Direct Bonding Mechanism of ALD-Al2O3 Thin Films
Authors: Beche Elodie , Fournel Frank , Larrey Vincent , Rieutord François , Morales Christophe , Charvet Anne-Marie , Madeira Florence , Audoit Guillaume , Fabbri Jean-Marc
Published: September 2014

Direct bonding mechanism of deposited alumina has been investigated from room temperature up to 1200°C. Through thermal treatments applied prior to direct bonding, it is shown that bonding interface quality can be linked to interface evolution between silicon and alumina thin film. Thanks to better understanding of bonding defect generation, high quality bonding interface using ALD-Al2O3 thin film have then been obtained. Even if some bonding results still deserve more investigations, a coherent direct bonding mechanism will be proposed.
Surface Inspection of Cu-Cu Non-Thermal Compression Bonding for Wafer-to-Wafer 3D Stacking
Authors: Kwon Doowon , Song Young-Uk , Kang Pilkyu , Oh Taeseok , Moon Chang-Rok , Lee Duckhyung
Published: September 2014

A new monitoring system combining SPD (Surface Potential Difference) imaging technique and XRD analysis has shown to be effective in understanding of plasma influence and monitoring plasma process in wafer bonding. This work will give a way to improve bonding yield in the hybrid Cu-Cu non-thermal compression bonding process through monitoring and optimizing plasma process conditions.
Low-Temperature Solid-State Bonding Using Hydrogen Radical Treated Solder for Optoelectronic and MEMS Packaging
Authors: Higurashi Eiji , Kawai Hiromu , Suga Tadatomo , Okada Sakie , Hagihara Taizoh
Published: September 2014

Low temperature hermetic sealing methods that are tolerant to surface roughness are required for optoelectronic and MEMS devices. In this paper, a new bonding process based on a solid-state interdiffusion between Sn and Au at a bonding temperature lower than 200 °C using hydrogen radical treated Sn-3.0Ag-0.5Cu (wt%) solder was developed. This is a fluxless bonding technique. The Sn-Ag-Cu solder patterns using hydrogen radical reflow process were exposed to air and bonded with Au thin films without flux at temperatures below the melting point. Successful bonding was obtained at a bonding temperature above 150 °C for 10 min. The samples bonded at a bonding temperature of 170 °C under the application of a bonding pressure of 150 MPa showed leakage rates of less than 1.0 × 10−9 Pa·m3 s−1.
Electrical, Mechanical, and Hermeticity Properties of Low-Temperature, Plasma Activated Direct Silicon Bonded Joints
Authors: Schjølberg-Henriksen Kari , Malik Nishant , Gundersen Elin Vold , Christiansen Oscar Rincon , Imenes Kristin , Moe Sigurd Teodor
Published: September 2014

The electrical, mechanical, and hermeticity properties of low-temperature, plasma activated direct silicon bonds were investigated. On individual dies with a bonding area ranging from 1 – 4 mm2, the bonded interface was found to have a capacitance ranging from 2.62 pF/mm2 – 2.89 pF/mm2 at 1 kHz. Linear I-V curves showing ohmic behavior without hysteresis and a resistance around 2.2 W were measured at DC voltage. We speculate that the capacitive and resistive responses are related to traps that are formed during the plasma activation process. The applied bonding process resulted in hermetic sealing with 100% yield on 2 × 481 dies. The maximum leak rate of the seals was 3.5 × 10-11 mbar×l×s-1, but could be significantly lower. No gross leaks were observed following a steady-state life test, a thermal shock test, and a moisture resistance test applied on 100 dies.
Detailed Investgations of Inner Cavity Pressure of MEMS Devices Sealed by Wafer Bonding
Authors: Knechtel Roy , Dempwolf Sophia , Hering Siegfried
Published: September 2014

Hermetic sealing is important regarding functionality and reliability for MEMS components. Typically this sealing is done at the wafer level using wafer bonding, which simultaneously also provides mechanical protective caps. An existing test structure for inner cavity pressure measurement, utilizing the pressure dependence of heat transfer in gasses, is used for detailed investigations of factors, which influence the inner cavity pressure in the wafer pre-processing and wafer bonding step itself. These investigations ultimately allowed optimized wafer processing, improved process control and reliability investigation.
(Invited) Room Temperature Bonding Using Thin Metal Films (Bonding Energy and Technical Potential)
Authors: Shimatsu Takehito , Uomoto Miyuki , Kon Hitoe
Published: September 2014

Room temperature bonding using thin metal films uses two flat wafer surfaces with sputter deposition. Then two films on wafers are bonded in vacuum or in air. Bonding in vacuum can be accomplished using almost any metal film, even with film thickness of a few angstroms on each side. The bonding energy is greater than the surface energy of metal films at thicknesses greater than the critical film thickness, which is related to the formation of thin reactive layers between metal films and wafers. Bonding in air using Au films also shows a bonding energy greater than the surface energy of Au films, even with an exposure time of Au films to air of 168 h (1 week). Bonding of wafers and mirror-polished metals was also achieved, which is effective for enhancing the heat dissipation efficiency.
(Plenary) Extending the FETs: Challenges and Opportunities for New Materials and Structures
Authors: Uchida Ken , Takahashi Tsunaki
Published: September 2014

Three-dimensional transistors where nanoscale Si films are utilized have attracted great interests because of better short channel immunity. In nanoscale Si, quantum effects on charged carriers become evident and an increase in the electron-phonon scattering rate results in lower thermal conductivity. Therefore, the device designers need to take into account the impact of quantum effects and channel temperature increase on electrical characteristics. In this work, quantum and interface effects which are more evident in nano-structures will be reviewed. Then, experimental evaluation of channel temperature increase (ΔT
ch) due to Joule heating and impact of ΔT
ch on analog performance of FETs utilizing nanoscale Si film will be shown.
Ni(SiGeSn) Metal Contact Formation on Low Bandgap Strained (Si)Ge(Sn) Semiconductors
Authors: Wirths Stephan , Troitsch Rene , Mussler Gregor , Zaumseil Peter , Hartmann Jean-Michel , Schroeder Thomas , Mantl Siegfried , Buca Dan
Published: September 2014

GeSn has gained a lot of attention as alternative high mobility and low bandgap material to boost the performance of MOSFETs and Tunnel-FETs as well as photodetectors. Self-aligned contacts with low sheet resistance and good thermal stability are desired for GeSn FETs. We present the formation of metallic contacts for high mobility Sn-based group IV semiconductors. The formation of ternary NiGeSn alloys for Sn compositions from 6 to 9 at.% and quaternary NiSiGeSn alloys, formed on SiGeSn ternaries with large Si/Sn compositions ratios are presented.
Liquid Phase Epitaxy (LPE) Formation of Localized High Quality and Mobility Ge & SiGe by High Dose Ge-Implantation with Laser Melt Annealing for 10nm and 7nm Node CMOS Technology
Authors: Borland John O , Sugitani Michiro , Oesterlin Peter , Johnson Walt , Buyuklimanli Temel , Hengstebeck Robert , Kennon Ethan , Jones Kevin Scott , Joshi Abhijeet
Published: September 2014

We investigated using high dose (5E16/cm2) Ge beam-line ion implantation in combination with laser melt annealing as an alternative to Ge-epi by CVD to form high quality single crystal Ge-epilayer by LPE (liquid phase epitaxy) that is very uniform, thin 10-25nm and localized for high mobility Ge-channels. The implant resulted in 7nm amorphous Ge deposition by a method called dose controlled deposition (DCD). A 515nm laser was used to vary the melt depth from 9nm to 500nm based on laser anneal pulse duration and power level. Ellipsometer was used to measure the surface amorphous layer thickness while therma-wave (TW) analysis was used to monitor Ge implant damage recovery after LPE. SIMS depth profiles showed Ge surface concentration varied from 100% down to 2% based on the laser melt depth. X-TEM analysis showed the transformation of deposited amorphous Ge surface layer to single crystal Ge after laser melt and LPE. Sb implantation at two dose levels of 3E15/cm2 and 3E13/cm2 was used to examine laser melt annealing effects on n-type dopant activation and electron mobility in Ge. Special Hx-probe tips on the 4PP system was required to measure sheet resistance and CAOT/DHE method was used for Differential Hall Effect measurements.
Silicon Diffusion Engineering in Rapid Melt Growth of Silicon-Germanium on Insulator
Authors: Littlejohns Callum G , Gardes Frederic Y , Nedeljkovic M. , Mashanovich Goran Z , Reed Graham T
Published: September 2014

In this paper we focus on developing an efficient method to obtain a crystalline SiGe layer on top of an insulator. The method is aimed at enabling the fabrication of different concentration of crystalline SiGe alloy through structure engineering. This technique could enable the alloy composition to be different by design across a single wafer by using a single Germanium deposition step.
Temperature Dependent Internal Friction Behavior of Single Crystal Germanium Studied by the Impulse Excitation Technique
Authors: Swarnakar Akhilesh Kumar , Van der Biest Omer , Van Humbeeck Jan , Vanhellemont Jan
Published: September 2014

The anelastic relaxation process in crystalline solids is influenced by various mechanisms including a.o. diffusion of point defects, dislocation formation, movement and multiplication. To analyze the type and concentration of relaxing units participating in a particular thermally activated process, measuring the temperature dependent internal friction is a well-known approach. In the present study, the impulse excitation technique was used to analyze the internal friction in single crystal Ge in the <111>-, <110>- and <100>- directions between room and melting temperature. The internal friction spectra reveal up to three internal friction peaks. To interpret the observed internal friction peaks, various aspects of the peaks such as activation energy, position and relaxation time will be discussed.
Investigation of Al-PMA Effect on Al2O3/GeOX/Ge Gate Stack
Authors: Nagatomi Yuta , Nagaoka Yuichi , Yamamoto Keisuke , Wang Dong , Nakashima Hiroshi
Published: September 2014

We investigated the Al post metallization annealing (PMA) effect on Al2O3/GeOX/Ge gate stacks. The Al-PMA is effective for Al2O3/GeOX/Ge gate stacks, similar to the case of SiO2/GeO2 gate stack. It was found that interface states density in the lower half of the band gap and slow trap density can be reduced by Al-PMA at 400°C. However, a serious problem occurred in the metal source/drain (S/D) MOSFET fabricated using the gate stack with Al-PMA, which was poor electrical isolation between gate and S/D. It was found that Al-PMA at 400°C caused the reaction of Al with Al2O3 film on the S/D side wall, resulting in a decrease in insulating quality of Al2O3 film. To solve this problem, we demonstrated a method for depositing a thin SiO2 film on the S/D side wall.
Structural and Optical Properties of Ge1-XSnx Alloys Grown on GaAs (001) by R. F. Magnetron Sputtering
Authors: Pérez Ladrón de Guevara Héctor , Rodríguez A. G. , Navarro-Contreras H. , Vidal M. a.
Published: September 2014

Ge1-xSnx alloys were grown on GaAs (001) substrates in a conventional R. F. magnetron sputtering system with two independent plasmas not simultaneous focus to substrate. We determined the in-plane and in-growth lattice parameters for different Sn concentrations by high resolution X-ray diffraction (HRXRD). We observed that Ge1-xSnx layers with low Sn concentrations have pseudomorphic characteristics. But this layers relax at Sn concentrations higher than the ones growth on Ge (001) substrates. Raman spectroscopy confirms the Sn concentrations of the Ge1-xSnx layers. We also determined the band gap transitions and we found that the indirect-direct band gap crossover occurs as is predicted in Ge1-xSnx alloys growth on Ge (001).
Optical Constants Determination of Pseudomorphic Si1-XGex Layers on Si(001), with 0<x<0.54
Authors: Nolot Emmanuel , Hartmann Jean-Michel , Hilfiker J.
Published: September 2014

The optical constants of fully strained Si1-xGex layers (0<x<0.54) alloys grown by Reduced Pressure Chemical Vapor Deposition on bulk Si(001) wafers were determined in the 0.73 to 6.48 eV spectral range using variable-angle spectroscopic ellipsometry. The robustness of the deduced optical functions relies on an appropriate management of surface effects together with a rigorous combination of X-ray based and optical-based analysis so as to build the required alloy model. This model was extensively tested, demonstrating a 0.5-1 at.% accuracy concerning the Ge content in fully-strained Si1-xGex epitaxial layers.
(Invited) Wrinkling Graphene with Bacteria and Functionalization of MoS2 for Electronic Applications
Authors: Briggs Donovan , Deng Shikai , Berry Vikas
Published: September 2014

Ultrathin two dimensional (2D) metal dichalogenide (MoS2, WS2, so forth) exhibits confinement of carriers, evolution of band structure, high on/off rectification, and high thermal absorption. However their incorporation into systems requires controlled functionalization and/or interaction with other nanoscale entities. Here, we enhance the stable sulfur/noble metal functionalization via both diffusion limited aggregation and instantaneous reaction arresting (using microwaves). These gold nanoparticles are incorporated selectively on MoS2 crystallographic edges (with 600 displacement). The Raman, electrical and thermal studies indicate a remarkably capacitive interaction between gold and thin MoS2 sheet (CAu-MoS2 = 2.17 mF/cm2), a low Schottky barrier (14.52 meV), a reduced carrier-transport thermal-barrier (253 to 44.18 meV after gold functionalization), and increased thermal conductivity (from 15 W/mK to 23 W/mK post gold deposition). This process provides a route to affiliate MoS2 with potential electronic application, such as electrodes attachment to hetero-structures of graphene and MoS2, where a gold film could be grown to act as an electron-tunneling gate-electrode connected to MoS2. Further, wrinkle-formation is exclusively exhibited by 2D nanomaterials, unlike their 0D and 1D counterparts. In graphene, these wrinkles can modify the electronic structure and states. We show wrinkles on graphene, their orientation and attributes (wavelength and amplitude) and that they obey the modified Herringbone model.
(Invited) Ge1-xSnx Optical Devices: Growth and Applications
Authors: Shimura Yosuke , Wang Wei , Vandervorst Wilfried , Gencarelli Federica , Gassenq Alban , Roelkens Gunther , Vantomme Andre , Caymax Matty , Loo Roger
Published: September 2014

We will introduce our Ge1-xSnx epitaxial growth process and we will illustrate its material quality by the performance of photodetectors containing a Ge/Ge1-xSnx /Ge quantum well with fully strained Ge1-xSnx layers. The photodetector responsivity in the short-wave infrared increases with Sn concentration, due to the shrinkage of the band gap. The use of multi quantum wells leads to a higher detector responsivity as the total absorption layer thickness is increased without undesired strain relaxation. The use of Ge1-xSnx as direct band gap material is expected to boost the efficiency of Ge based photodetectors even further but it requires relaxed Ge1-xSnx layers. An improvement of the surface quality of the epitaxial Ge1-xSnx in terms of Sn agglomeration has been achieved by freezing Sn atoms (which is realized by using a high precursor partial pressure and the surfactant effect of hydrogen) into the subsurface of the Ge1-xSnx layers.
Growth and Characterization of Epitaxial Ge1-XSnx Alloys and Heterostructures Using a Commercial CVD System
Authors: Margetis Joe , Ghetmiri Seyed Amir , Du Wei , Conley Benjamin R , Mosleh Aboozar , Soref Richard , Sun Greg , Domulevicz Lucas , Naseem Hameed A , Yu Shui-Qing , Tolle John
Published: September 2014

Fully strained and relaxed epitaxial Ge1-xSnx alloys with Sn contents up to 12 at. % have been grown on Ge buffered Si using an Epsilon® 2000 Plus commercial chemical vapor deposition system. Using a specialized growth approach intrinsic, p-type, and n-type alloys have been demonstrated. Material and optical characterization of these alloys indicate that the alloys are of high crystal quality in which the Sn is fully substitutional. Heterostructures of doped Ge/Ge1-xSnx/Ge have also grown to demonstrate their application in light emitting and detecting devices. Phosphorus doped Ge1-xSnx photoluminescence has also been observed at wavelengths up to 2.4 μm. Growth, materials and optical properties of these materials will be discussed.
(Invited) Waveguide Germanium PIN Photodiodes for Optical Communication Applications
Authors: Vivien Laurent , Virot Léopold , Hartmann Jean-Michel , Fédéli jean-Marc , Marris-Morini Delphine , Cassan Eric , Baudot Charles , Boeuf Frédéric
Published: September 2014

The potential of silicon photonics for optical telecommunications and optical interconnects in microelectronics circuits has clearly been demonstrated. The possibility of reducing system costs and increasing the number of functionalities on the very same integrated chip by combining photonics and electronics is of great importance. In this paper, we will present recent results on 40Gbit/s germanium photodetectors integrated in silicon on insulator (SOI) waveguides. A 40Gbit/s integrated optical link including silicon optical modulator and Ge photodetector has been fabricated to demonstrate the capability of such a technology. All devices have been processed in a 300mm pilot line to have access to state of the art technology.
Evaluation of Anisotropic Biaxial Stress in Thin Strained-SiGe Layer Using Surface Enhanced Raman Spectroscopy
Authors: Yamamoto Shotaro , Kosemura Daisuke , C.M.Yusoff S.Norhidayah , Kijima Takahiro , Imai Ryosuke , Takeuchi Kazuma , Yokogawa Ryo , Usuda Koji , Ogura Atsushi
Published: September 2014

We applied surface-enhanced Raman spectroscopy (SERS) to the excitation of transversal optical (TO) phonos in strained SiGe. The SERS technique can greatly enhance the Raman signal owing to metal-surface plasmon resonance. Furthermore, the electrical field includes a large amount of z-polarization, which can excite TO phonons. In this study, we evaluated anisotropic biaxial stress state in thin strained-SiGe layer on a Si substrate with the SERS technique.
(Invited) Germanium-Tin P-Channel Field-Effect Transistor with Low-Temperature Si2H6 Passivation
Authors: Gong Xiao , Yang Yue , Guo Pengfei , Wang Wei , Cheng Ran , Wang Lanxiang , Tok Eng Soon , Yeo Y. C.
Published: September 2014

In the past decade, significant effort has been made in the research community to search for alternative high mobility channel materials as replacement for silicon which has been the dominant channel material in complementary metal-oxide-semiconductor (CMOS) technology for almost 50 years. Among possible candidates, Germanium-tin (GeSn) has high hole mobility and is a promising channel material for scaling the supply voltage towards 0.5 V for high-performance p-channel field-effect transistors (pFETs) in the sub-10 nm technology nodes. In this paper, we discuss the research and development of using GeSn as the channel material of pFETs for enhancing the hole mobility and drive current. This includes GeSn planar pFETs, GeSn nanowire (NW) pFETs, as well as GeSn tunneling FETs (TFETs). Low-temperature Si2H6 passivation was developed to realize high-quality gate stack on GeSn.
Stability of Pseudomorphic and Compressively Strained Ge1-XSnx Thin Films under Rapid Thermal Annealing
Authors: Conley Benjamin R , Mosleh Aboozar , Ghetmiri Seyed Amir , Du Wei , Sun Greg , Soref Richard , Margetis Joe , Tolle John , Naseem Hameed A , Yu Shui-Qing
Published: September 2014

Thin film Ge1-xSnx with Sn mole fractions up to 7 % were grown using chemical vapor deposition on Si substrates with a relaxed Ge buffer. Rapid thermal annealing at 550 to 700 °C resulted in film relaxation and Sn segregation. X-ray diffraction rocking curves and reciprocal space mapping of the films showed a reduction in strain after annealing. Samples with Sn mole fractions of 3.2, 6.0, and 7.0 % were partially relaxed when annealed above 550 °C for 30 seconds. Raman spectroscopy of the Ge-Ge longitudinal optical phonon showed a red shift for samples with Sn mole fraction ≤ 6 %, which indicates an increase in Sn atom incorporation within the lattice due to annealing. Photoluminescence measurements of CMOS compatible annealing below 450 °C showed an initial reduction in film quality for short time annealing, but an increase in photoluminescence intensity was observed for longer annealing time.
(Invited) Integrating Classical Semiconductor Devices with Si/Sige Quantum Dots
Authors: Ward Daniel R , Foote Ryan H , Gamble John King , Savage Donald E , Lagally Max G , Coppersmith Susan N , Eriksson Mark A
Published: September 2014

As semiconductor based quantum devices scale up from single to multiple qubits there is an increasing need to integrate classical semiconductor based devices to manage and generate control signals. We discuss progress on integrating field-effect transistors with planar quantum dot devices to achieve a high throughput of device testing by creating on-chip multiplexers for our devices. Using the on-chip multiplexers we can overcome the challenge of the limited number of electrical connections available in a typical dilution refrigerator while still working at the milliKelvin temperatures necessary for quantum operations. We also discuss recent advances in device design that aim to improve the performance of Si/SiGe quantum dot-based qubits.
Very Low Temperature (Cyclic) Deposition / Etch of In-Situ Raised Sources and Drains
Authors: Hartmann Jean-Michel , Benevent Véronique , André Agathe , Sirisopanaporn Chutchamon , Veillerot Marc , Samson Marie-Pierre , Barraud Sylvain
Published: September 2014

We have developed an innovative 500°C process for the selective deposition of SiGe:B Raised Sources and Drains (RSDs). We have first of all studied on blanket Si wafers the in-situ boron doping of SiGe with Si2H6, GeH4 and B2H6. A growth rate increase by a factor higher than 4 together with a Ge concentration decrease from 45% down to 28% occurred as the diborane mass-flow increased (at 500°C, 20 Torr). Very high substitutional boron concentrations were achieved (~ 5x1020 cm-3) in layers that were single crystalline and flat. Adding large amounts of HCl to the gaseous mixture did not yield the selectivity aimed for on SiO2-covered Si wafers, however. To that end, we have thus benchmarked various 500°C Cyclic Deposition / Etch (CDE) processes. 12 cycles CDE processes were characterized by HCl etch rates of poly-SiGe:B that were either too low to be of any practical use or yielded 3 dimensional SiGe:B layers on Si(001). Straightforward Deposition / Etch (DE) processes, with the HCl selective etch of poly-SiGe:B carried out at 740 Torr (i.e. atmospheric pressure), enabled us by contrast to achieve selectivity on SiO2 while retaining single crystalline if slightly rough SiGe:B layers. Those DE processes were tested on patterned Silicon-On-Insulator substrates with gate stacks. Longer HCl etch times than the ones identified on blanket wafers were key in getting rid of poly-SiGe:B on top of dielectrics covered surfaces; rather smooth, facetted SiGe:B RSDs were obtained in the end.
Characterization of Epitaxial Si:C:P and Si:P Layers for Source/Drain Formation in Advanced Bulk FinFETs
Authors: Rosseel Erik , Profijt Harald Benjamin , Hikavyy Andriy Yakovitch , Tolle John , Kubicek Stefan , Mannaert Geert , L'abbe Caroline , Wostyn Kurt , Horiguchi Naoto , Clarysse Trudo , Parmentier Brigitte , Dhayalan Sathishkumar , Bender Hugo , Maes Jan Willem , Mehta Sandeep , Loo Roger
Published: September 2014

Uniaxial stressors have received much interest over the last few years as a method to enhance carrier mobility and, hence, drive current with minimal modification to the structure of the transistor. However, the shift in device design to complex structures with multiple crystallographic orientations like advanced bulk-FinFETs has significantly complicated the incorporation of mobility enhancing stressors. For the n-FinFET in particular, it turns out that the crystal quality and growth rate of Si:P and Si:C:P films can be strongly dependent upon the crystallographic orientation of the starting surface. Both for raised and recessed epi we find that formation of (111) facets and twin defects occurs already after a limited growth on the fin. Besides the growth on raised and recessed fins, we also discuss the resistivity increase in Si:C:P layers as a function of carbon content and demonstrate that laser annealed Si:P films with high phosphorus content (e.g. 4% or higher) can be considered as potential alternatives to Si:C:P with a lower resistivity for the same strain.
SiC Power Devices in a Soft Switching Converter, Including Aspects on Packaging
Authors: Ranstad Per , Giezendanner Florian , Bakowski Mietek , Lim Jang-Kwon , Tolstoy Georg , Ranstad Anton
Published: September 2014

In many applications of power electronic converters efficiency and size are important figures of merit. Low losses in the power semiconductors as well as high frequency operation are important factors to obtain compact and highly efficient converters. The converters considered in this paper are off-line industrial power supplies (~100 kW) operating at a switching frequency range of 20-40 kHz. Replacing Si power devices by SiC counterparts enables both lower losses and increased switching frequencies. In this paper, experimental results from SiC PiN diodes, (output rectifiers) and SiC MOSFETs, (active switches) are presented.
Atomic Layer Deposition of Nanostructured Tunable Resistance Coatings: Growth, Characterization, and Electrical Properties
Authors: Mane Anil U. , Tong William M. , Brodie Alan D. , McCord Mark A. , Elam Jeffrey W.
Published: September 2014

We have developed atomic layer deposition (ALD) methods to synthesize robust nanostructured composite coatings with tunable resistance comprised of conducting, metallic nanoparticles embedded in an amorphous dielectric matrix. These films are nominally composed of M:Al2O3 where M= W or Mo, and are prepared using alternating exposures to trimethyl aluminum (TMA) and H2O for Al2O3 ALD and alternating MF6/Si2H6 exposures for the metal ALD. By varying the ratio of ALD cycles for the metal and Al2O3 components in the film, we can precisely adjust the resistivity of these composite coatings over a very broad range (e.g. 1012-103 Ohm-cm). Furthermore, the self-limiting nature of ALD allows us to grow these nanocomposite films on a variety of complex substrates such as high aspect ratio porous 3D surfaces, MEMS devices, ceramics, grid structures and microchannel plates. Here we present a detailed ALD study of the nanostructured composite resistance coatings including in-situ material growth, microstructural characterization, and electrical measurements.
Study of Y2O3 Thin Film Prepared by Plasma Enhanced Atomic Layer Deposition
Authors: Cho Gu Young , Noh Seungtak , Lee Yoon Ho , Ji Sanghoon , Cha Suk Won
Published: September 2014

Y2O3 thin films are fabricated on Si (100) wafer by using showerhead type direct PEALD system. The commercial tris (methylcyclopenta dienyl) yttrium ((MeCp3)3Y) precursor and oxygen plasma are used as a precursor and as a reactant. The growth rate per cycle is increased slightly from 0.1nm/cycle to 0.13nm/cycle, as the substrate temperature is increased from 175¢ªC to 325¢ªC. The crystallinity and density of Y2O3 thin films are also increased as the substrate temperature is increased. Carbon contaminations and film stoichiometry are improved due to high reactivity of plasma species. Dielectric constants of Y2O3 thin films are in range of 15~17 calculated by capacitance – voltage characteristics.
In-Situ Studies on 2D Materials
Authors: Wallace Robert M
Published: September 2014

The investigation of 2D materials such as graphene and transition metal dichalcogenides for beyond CMOS device concepts emphasizes the importance of surface and interfacial reactions. A fundamental understanding of such reactions in the context of materials integration for devices greatly benefits from in situ characterization methods where processes such as surface cleaning, film deposition, and annealing can be simulated and subsequently correlated to device behavior. This paper summarizes our recent work on in situ characterization of 2D materials in the context of device applications and the correlation of the physical and electrical characterization.
RF Power Effect of Post-Deposition Oxygen Plasma Treatment on HfO2 Gate Dielectrics
Authors: Bo Tian-Cih , Cheng Yi-Lung
Published: September 2014

The radio frequency (RF) power effect of post-deposition O2 plasma treatment on the physical, electrical, and reliability characteristics of high-k HfO2 dielectric films were comprehensively investigated in this study. The experimental results indicated that increasing the RF power of post-deposition O2 plasma treatment resulted in a stoichiometric HfO2 film, but led to a thinner interfacial layer and the formation of new Hf-Si bonds. Additionally, the electrical performance and reliability of HfO2 dielectric films were significantly impacted by the RF power of the post-deposition O2 plasma treatment. As RF power is less than 30 W, the leakage current density and time-to-breakdown of the O2 plasma-treated HfO2 films were improved in comparison with those of the as-deposited samples. However, further increasing RF power to exceed 50 W would cause the continuous degradation in the electrical performance and reliability due to the plasma damage induced by oxygen active spices in a plasma environment. Therefore, performing a post-deposition O2 plasma treatment process on the as-deposited HfO2 dielectric films can effectively improve the dielectric's properties. However, the applied RF power is an essential controlling parameter, avoiding serious plasma damage occurrence.
Mechanical/Structural Properties of ALD Zirconium Oxide (ZrO2) Thin Films for High-Tech Applications
Authors: Mamun M A , Baumgart Helmut , Elmustafa A A
Published: September 2014

Zirconium oxide (ZrO2) films of varying thickness were deposited on p-type Si (100) substrates using Atomic layer deposition (ALD) with 200, 300, and 500, ALD cycles. The 300 ALD deposition cycle films were further annealed at 600 °C. We tested these ZrO2films for structural and nanomechanical properties using nanoindentation and investigated the surface morphology by AFM. The structural and surface properties were explored using scanning field emission electron microscopy (FE-SEM) and atomic force microscopy (AFM). We discuss the influence of the deposition technique on the structure and properties of the ZrO2 films resulting from ALD synthesis. The nanoindentation results indicate that the films become consistently softer as the number of ALD deposition cycles increase and the film thickness grows larger. Further annealing of the films slightly enhanced the hardness and fracture toughness of the films. The annealed ALD films depicted shorter radial cracks compared to the films under the same applied stress, which were not annealed in forming gas.
The Effect of SPA-SiO2 Tunnel Oxide Thickness for Metal-Insulator-Silicon Photoelectrochemical Cells
Authors: Scheuermann Andrew G. , Lu David Q. , Ito Toru , Chidsey Christopher E.D. , McIntyre Paul C.
Published: September 2014

The photoelectrochemical properties of metal-insulator-silicon cells with varying SiO2 thickness are studied using slot-plane-antenna (SPA) growth. This method can produce ultrathin films with precise thickness at low temperatures. N-type silicon photoanodes and degenerately doped p-type silicon anodes are fabricated with SPA-SiO2, compared to devices with chemical-SiO2, and found to produce similar results to previous studies. The electrochemical performance of SPA-SiO2 oxides of varying thickness is measured and modeled in order to map the trend of performance with varying thickness. The modeled resistance of charge transfer in ferri/ferrocyanide is found to increase exponentially with SiO2 thickness in agreement with a quantum tunneling mechanism expected for a tunnel junction and notably different from previous behavior observed for ALD-TiO2/SiO2 anodes. These findings are set in context of the goal of fabricating devices optimized for both efficiency and long-term stability.
Self Assembled Metamaterials Formed via Plasma Enhanced ALD of Ag Thin Films
Authors: Prokes S. M. , Glembocki Orest J.
Published: September 2014

We have investigated the novel optical behavior of Ag metal deposited via plasma enhanced atomic layer deposition (PEALD). This material exhibits unexpected plasmonic properties and the plasmonic enhancement is dependent on the unique microstructure of the Ag film. Electromagnetic field simulations indicate that this optical behavior is due to air gaps that are an inherent property of the mosaic-like microstructure of the PEALD-grown Ag film. We have also investigated the effect of modifying these air gaps, and the development of flexible plasmonic materials, using this unique metamaterial.
(Invited) Thin Film Transistors as Driving Devices for Attached Devices
Authors: Kuo Yue , Chang Geng-Wei
Published: September 2014

TFTs can be used as driving or detecting devices for purposes of optical, chemical, or biological sensing, imaging, displays, etc. Assuming the stability is not an issue, the poly-Si, IGZO, and a-Si:H TFTs were compared with respect to the device driving capability. For the drain-attached device, the maximum available power is determined by the device’s resistance and the TFT’s on-current. For the gate-attached device, the study is based on connecting a resistor and a capacitor in parallel. The raise or decay of the drain current is dependent on the RC time delay. Although the high mobility TFT has many advnatages, the low mobility TFT is adequate for certain applications. In real applications, the manufactuability and cost are important factors in choosing the TFT.
Nonvolatile Memory Device Using Mobile Protons via Insertion Hydrogen Neutral Beam Treatment Process between SiO2 Deposition Processes at Room Temperature
Authors: Jang Jin Nyoung , Lee Dong hyeok , Jeon Sanghun , Park Jeunghak , Hong MunPyo
Published: September 2014

We demonstrated the nonvolatile memory functionality of nano-crystalline silicon (nc-Si) thin film transistors (TFTs) using mobile protons that are generated by very short time hydrogen neutral beam (H-NB) treatment at room temperature (25 °C). The whole memory fabrication process kept under 50 °C (except SiO2 deposition process; 300 °C). These nc-Si devices exhibited reproducible hysteresis, reversible switching, and nonvolatile memory behaviors in comparison with those of the conventional FET devices. Our study will further provide a useful route of creating memory functionality and incorporating proton-based storage elements onto a probability of next generation flexible memorable electronics such as low power consumption flexible display panel.
(Invited) Pedagogical Approach for Higher Education in Microelectronics and Nanotechnologies in France: Specific Actions on the Thin Film Technologies
Authors: Bonnaud Olivier , Mohammed-Brahim Tayeb , Bsiesy Ahmad
Published: September 2014

The microelectronics field is in a strong evolution since more than 50 years. To maintain the level of the related diplomas, the universities must permanently adapt the education in order to follow this evolution. This supposes to dispose of facilities as well in computer aided design as in fabrication processes. These facilities are available in the 12 common centers of the French national network, the GIP-CFNM. Aiming to maintain both, quality and attractiveness to students, its mission is based on strategy of innovative projects. Since 2009, many projects were selected in order to develop new activities in the thin film devices. We can mention CMOS-like thin film transistors based circuits, magnet, pressure and mechanical sensors, flexible electronics, organics devices, or sensors based on a suspended membrane and applied to chemical and biologic detectors. This paper presents the national network and the results of its strategy in thin film technologies.
Absolute Value Determination of Vacancy Concentration in Silicon Crystals Using Low-Temperature Ultrasonic Measurements
Authors: Yamada-Kaneta Hiroshi , Okabe Kazuki , Akatsu Mitsuhiro , Baba Shotaro , Mitsumoto Keisuke , Nemoto Yuichi , Goto Terutaka , Saito Hiroyuki , Kashima Kazuhiko , Saito Yoshihiko
Published: September 2014

For the samples taken from the void region of the CZ silicon crystal grown with the same solidification condition and different thermal histories after the solidification, we measure the magnitude S of the elastic softening which is proportional to the concentration of the single vacancies [V]. For these samples, we also measure the size distribution of the void density by using the infrared light-scattering tomography, to evaluate the concentration [Vc] of the vacancies consumed for the void formation. From these two experiments, we find a sum rule [Vc] + a S= C, where C depends only on the solidification condition and is independent of the thermal history after the solidification. This enables us to find the conservation rule of the vacancies [Vc] + [V] = C. The value of the proportionality constant a in the relation [V] = a S is determined. Demonstration of determining the absolute values of [V] from the measured S is given. An estimate is made for the value of the quadrupole-strain coupling constant.
(Invited) Oxygen Precipitation and Defect Generation in Cz Silicon during Second and Millisecond Annealing
Authors: Kissinger Gudrun Helga , Kot Dawid , Schubert Markus Andreas , Sattler Andreas
Published: September 2014

The precipitation of oxygen was investigated after rapid thermal annealing pre-treatments for 30 s in the range 1100-1250 °C and after flash lamp annealing for 3 ms and 20 ms with different irradiances up to melting of the wafer surface. It was found that the difference between thermal processing on the second and on the millisecond scales is based on the temperature profiles generated by the different types of processing. These profiles influence the shrinking of grown-in oxide precipitate nuclei and the generation, diffusion, and annihilation of intrinsic point defects. It was further found that pre-existing dislocations propagate into the wafer during flash anneals. The dislocation propagation can be well described by a three-dimensional mechanical model.
Morphology of Oxygen Precipitates in RTA Pre-Treated Czochralski Silicon Wafers Investigated by FTIR Spectroscopy and STEM
Authors: Kot Dawid , Kissinger Gudrun , Schubert Markus Andreas , Sattler Andreas
Published: September 2014

The influence of RTA pre-treatments at 1250 °C on the morphology and stoichiometry of oxygen precipitates was investigated by STEM and FTIR. The morphology of the oxygen precipitates depends on the temperature of the subsequent annealing. Annealing at 800 °C results first of all in the formation of 3D dendritic precipitates while during annealing at 900 °C or 1000 °C mainly plate-like and octahedral precipitates are formed. The absorption bands of the dendritic SiO
x
precipitates were identified and simulated based on effective medium theory. All regular plate-like and octahedral precipitates could be well fitted assuming x=2.
Ab Initio Analysis on Stability of Metal Atoms in β-Si3N4/Si Structure
Authors: Shibata Daiki , Kobayashi Syunsuke , Sueoka Koji , Komachi Jun , Saga Koichiro
Published: September 2014

We have analyzed the metal behavior in the SiN/Si structure with density functional theory. The structure of SiN film was assumed to be a β-Si3N4 single crystal. We separated the SiN/Si structure into three models: first, β-Si3N4 bulk model for inside the SiN thin film; second, interface model of β-Si3N4/Si, and third, Si bulk model for Si substrate. Furthermore, Cr, Fe, Ni, Cu or W atom was placed in each model and the geometry optimization was performed to evaluate the formation energy. The order of the calculated formation energy of each metal in β-Si3N4/Si structure is W > Cr, Fe > Cu, Ni. By using the calculated values of formation energy of these metals, we explained the experimental results to some extent.
(Invited) Defect Generation Mechanism and Its Impact on Reliability Properties in MONOS Devices
Authors: Fujii Shosuke , Kusai Haruka , Sakuma Kiwamu , Koyama Masato
Published: September 2014

The interface-state generation mechanism and its impact on reliability properties, such as endurance and data retention, in MONOS devices have been studied. The charge measurement technique we developed has demonstrated that holes injected during erasing are the main cause of interface-state generation. From carrier separation measurement for MONOS devices, we have found the data retention degradation after P/E stress is owing to the increased hole injection from Si substrate via the generated interface states. We also discuss the physical origin of the interface states in MONOS devices and report on MONOS-specific interface-state generation/recovery phenomena, and their significant impact on endurance and retention properties.
Temperature Effect on Memory Functions of the nc-CdSe Embedded ZrHfO High-k MOS Device
Authors: Zhang Shumao , Kuo Yue
Published: September 2014

The temperature effect on the memory characteristics of the MOS capacitor containing the nanocrystalline CdSe embedded ZrHfO high-k gate dielectric has been investigated. At the high temperature, the Coulomb blockade phenomenon is suppressed and the leakage current is increased due to the relative high conductivity of the dielectric film. At the same time, the density of interface states is high and the memory window is small. When the temperature is increased, the hole trapping capacity is enhanced because of the improve the supply of holes from the Si. However, the electron trapping capacity is reduced because of the easy transfer of electrons through the high-k stack. The frequency dispersion phenomenon is enhanced at the high temperature. The temperature has strong influence on the carrier generation, transport, and trapping at the interface and the bulk film.
(Invited) Detection of the Secretome and Transfection of a Single Cell Using a Nanopore
Authors: Kurz Volker , Nelson Edward , Tanaka Tetsuya , Timp Gregory
Published: September 2014

The secretome offers the prospect of new biomarkers for the diagnosis of disease and a promising approach to drug discovery. However, these proteins are secreted in only minute amounts. We propose to use a nanopore to both transfect single cells with nucleic acids and detect secreted protein.
(Invited) Nanowire Field-Effect Transistor-Based Biosensors as a Tool for Life Science
Authors: Chen Yit-Tsong
Published: September 2014

Electrical biosensors based on silicon nanowire field-effect transistors (SiNW-FETs) have attracted enormous interest in the biosensing field. SiNW-FETs have proven to be significant and efficient in detecting diverse biomolecular species with the advantages of high probing sensitivity, target selectivity, real-time recording, and label-free detection. In recent years, significant advances in biosensors have been achieved, particularly for cellular investigation and biomedical diagnosis. In this paper, we will report on the recent achievements with SiNW-FET biosensors for the fast screening of protein-protein interaction and sensitive detection of neurotransmitters release from live cells. Despite these remarkable achievements, certain improvements remain necessary in the device performance and clinical applications of FET-based biosensors; thus, several prospects about the future development of nanowire transistor-based instruments for biosensing employments are discussed at the end of this paper.
A Quick and a Flexible Hydride Vapor Phase Epitaxy Process to Achieve Buried Heterostructure Quantum Cascade Lasers
Authors: Metaferia Wondwosen , Simozrag Bouzid , Junesand Carl , Sun Yan-Ting , Carras Mathieu , Lourdudoss Sebastian
Published: September 2014

BH-QCLs were fabricated with regrowth of semi-insulating InP:Fe in hydride vapor phase epitaxy reactor. Two types of lateral ridge QCL designs were considered: (i) closely spaced ridges with double trenches and (ii) widely and uniformly spaced ridges. The etched depth varies from 6 to 15 µm in the former and 6 to10 µm in the latter. Double trenches of about 14 µm deep take only < 40 minutes to planarize while the same time is needed to planarize about 8 µm deep trenches with uniform ridges. In any case the achieved growth rate is higher by at least one order of magnitude than that can be achieved in MBE and MOVPE. Some fabricated BH-QCLs are characterized and they exhibit spatially monomode (TMoo) laser with an output power of as high as 2.4 W and wall plug efficiency of ~8-9% at RT under CW operation.
The Perturbation Bound for the Spectral Radius of a Nonnegative Tensor
Authors: Li Wen , Ng Michael K.
Published: September 2014

We study the perturbation bound for the spectral radius of an mth-order n-dimensional nonnegative tensor A. The main contribution of this paper is to show that when A is perturbed to a nonnegative tensor A~ by ΔA, the absolute difference between the spectral radii of A and A~ is bounded by the largest magnitude of the ratio of the ith component of ΔAxm-1 and the ith component xm-1, where x is an eigenvector associated with the largest eigenvalue of A in magnitude and its entries are positive. We further derive the bound in terms of the entries of A only when x is not known in advance. Based on the perturbation analysis, we make use of the NQZ algorithm
to estimate the spectral radius of a nonnegative tensor in general. On the other hand, we study the backward error matrix ΔA and obtain its smallest error bound for its perturbed largest eigenvalue and associated eigenvector of an irreducible nonnegative tensor. Based on the backward error analysis, we can estimate the stability of computation of the largest eigenvalue of an irreducible nonnegative tensor by the NQZ algorithm. Numerical examples are presented to illustrate the theoretical results of our perturbation analysis.