bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrathin NO/N2O Oxynitride Dielectric For Advanced Flash Memory Application: Single Wafer and Batch Technology
Authors: Zonca R. , Crivelli B. , Polignano M. L. , Cazzaniga F. , Alessandri M. , Caricato A. P. , Bersani M. , Sbetti M. , Vanzetti L. , Xing G. C. , Miner G. E. , Astici N. , Kuppurao S. , Lopes D. , Nesso S. 
Published: April 2011

ABSTRACTIn this paper a systematic investigation of nitrided oxides obtained by Rapid Thermal Oxidation/Nitridation (RTO/RTN) in AMAT Centura System is reported. Two different aspects were considered: first the comparison between single wafers and batch technology, second the different possible oxide architecture achievable with RTO/RTN system (i.e. RTO + RTN, RTN + RTO, RTN + RTO + RTN). Both morphological and patterned wafers were processed. Physical and chemical characterizations were carried out by means of SIMS, XPS, ELYMAT, AFM and Etching Rate studies. Morphological results were then correlated to electrical data obtained on MOS capacitors. The film obtained performing a NO RTN nitridation of the native oxide followed by a ISSG (In Situ Steam Generation) oxidation exhibited very promising electrical properties that made it an appealing candidate as gate dielectric in CMOS and Flash memories applications.
Microscopic and Theoretical Investigations of the Si-SiO2 Interface
Authors: Duscher G. , Buzcko R. , Pennycook S. J. , Pantelides S. T. , Müllejans H. , Rühle M. 
Published: April 2011

ABSTRACTZ-contrast imaging and electron energy-loss spectroscopy with a spatial resolution at the atomic scale provide evidence of an atomically abrupt Si-SiO2, interface. Th micrographs revealed no indication for an interface layer of crystalline oxide at this thermally grown interface. Theoretical ab-initio calculations of two different interface structures showed that even in the most ideal interface the local density of states extends into the region of the oxide band gap. The O-K energy-loss near-edge structure was simulated for both interface models. The comparison of theoretical and experimental results of the O-K near-edge structure agreed and showed that states below the conduction band of the oxide are caused by the dimer-like SiO-Si bridges present in all structural models.
Room Temperature Ultraviolet Photoluminescence from 800°C Thermally Oxidized Si1−x−yGexCy Thin Films on Si(100) Substrate
Authors: Cheng X. M. , Zheng Y. D. , Zang L. , Liu X. B. , Zhu S. M. , Lo Z. Y. , Han P. , Jiang R.L. 
Published: April 2011

ABSTRACTThe thermally oxidized Si1−x−yGexCy thin films were grown on silicon substrates by Plasma-enhanced Chemical Vapor Deposition (PECVD) and then wet oxidized at 800°C for 20 minutes. Photoluminescence spectra of the samples were measured at room temperature under 250nm excitation. Two ultraviolet photoluminescence bands with the peaks at ∼370nm and ∼396nm were observed in the oxidized samples. Possible mechanism of this photoluminescence is discussed.
Characterization of the Pb1 Interface Defect in Thermal (100)Si/SiO2 by Electron Spin Resonance: 29Si Hyperfine Structure and Electrical Relevance
Authors: Stesmans A. L. 
Published: April 2011

ABSTRACTOptimized electron spin resonance investigation resulted in the observation of the fuill angular dependence of the hyperfine (hi) spectra of the Pb1 interface defect in thermal (100)Si/SiO2, showing that the dominant hf interaction of the associated unpaired electron arises from a single Si site. The defect is identified as a prototype Si dangling bond defect with, much remarkably, the unpaired sp3-orbital pointing closely along a <211> direction at 35.26° with the [100] interface normal. If O is excluded as an immediate part of the defect, the key part of the Pb1 defect is uncovered as a tilted Si3≡Si unit. The incorporation of this defect kernel into a larger defect structure is analyzed within the framework of theoretical insight, suggesting the moiety to be part of a strained interfacial Si-Si dimer. ESR has been combined with electrical measurements to monitor the defect's behavior under thermal treatment, including postoxidation annealing in various ambients. No electrical activity of Pb1 as a detrimental interface trap could be traced, suggesting the defect to be of little relevance for device performance. The results are reviewed and discussed in the light of the defect's characteristic appearance at the (100)Si/SiO2 interface.
Challenges in Interface Trap Characterization of Deep Sub-Micron MOS Devices Using Charge Pumping Techniques
Authors: Autran J.L. , Masson P. , Ghibaudo G. 
Published: April 2011

ABSTRACTThis work surveys some of our recent experimental and theoretical advances in charge pumping for the electrical characterization of interface traps present in MOSFET architectures. The first part of this paper is devoted to an improved time-domain analysis of the charge pumping phenomenon. This approach presents the main advantage to use the same formalism to describe the charge pumping contribution of a single trap or a continuum of traps at the Si-SiO2 interface. The implications for deepsubmicron MOSFET characterization are illustrated. Some experimental aspects are then presented, including the adaptation of the technique to ultra-thin oxides, non-planar oxides and DRAM memory cells. Finally, recent charge pumping characterization results are reported concerning the electrical behavior of the Si-SiO2 interface submitted to particular technological treatments, electrical and radiation stresses, or post-degradation anneals.
Surface and Interfacial Topography of Oxides on Si(111) With Ultra-Low Atomic Step Density
Authors: Oliver Antonio C. , Blakely Jack M. 
Published: April 2011

ABSTRACTAtomic force microscopy has been used to study the morphology of the oxide surface and the Si-SiO2 interface after oxidation of Si(111) surfaces that are either totally free of atomic steps or have well characterized low step density. The step-free areas were formed by thermally processing a patterned Si surface in which flat areas are enclosed by a square array of ridges; flow of the atomic steps into the surrounding ridge barriers produces a regular array of step-free areas each of which can be up to ∼50µm×50µm. Arrays of widely spaced steps (e.g. 5µm) can also be produced in the step-free areas. AFM scans of the same areas were taken prior to (dry) oxidation, after oxidation, and after chemical removal of the oxide. It was found that at an oxide thickness in the 5-13nm range, the initial step structure of the underlying Si substrates is translated through the oxide to the surface after oxidation with the oxide surface being somewhat rougher than the initial substrate. Furthermore, the initial step morphology of the substrate remains at the Si-SiO2 interface after etching away the oxide by HF. The interface roughness is less than that of the oxide surface. The results suggest that the initial oxidation of silicon proceeds in a ‘layer by layer’ manner and not through a preferential step-flow oxide growth mode.
Influence of Pre and Post Process Conditions on the Composition of Thin Si3N4 Thin Films (3 nm) Studied by XPS and TOFSIMS
Authors: Conard T. , Witte H. De , Vandervorst W. , Houssa M. , Heyns M. , Pomarede C. , Werkhoven C. 
Published: April 2011

ABSTRACTWith the downscaling of the electronic devices and the increase in the frequency of the electronic circuits, a large search for new gate dielectric is ongoing. The exact composition and element distribution in the dielectric film have a large impact on the electrical characteristics of these films. We studied here the formation of ultrathin Si3N4 films (3 nm) under different conditions and concentrated on their composition analysis. The Si substrates were cleaned using RCA and/or HF dip. The Si3N4 films were subsequently fabricated either by RTCVD (SiH4/NH3) either by remote plasma (SiH4/N2) with or without a pre-anneal to form a 0.5 nm SiO2 layer. Post annealing was made using NO, N2O or NH3 at various temperatures and for various times. The quantification of the composition was realized using XPS and elemental distribution was analyzed using TOFSIMS with Ar+ sputtering and positive ion detection mode.The results show that the fabrication method of the nitride film has only a very limited influence on the O/N content of the films. However, both the preparations of the substrate (HF last or RCA last) and the post-annealing influence strongly the film composition. The presence of an interfacial oxide increases significantly the oxygen content of the film. Post-annealing with N2O also increases the oxygen content of the film while the NH3 post-annealing leads to a significant decrease. The results are compared with electrical characterization of the same films.
Highly Reliable Thin Hafnium Oxide Gate Dielectric
Authors: Kang Laegu , Lee Byoung-Hun , Qi Wen-Jie , Jeon Yong-Joo , Nieh Renee , Gopalan Sundar , Onishi Katsunori , Lee Jack C. 
Published: April 2011

ABSTRACTHfO2 is the one of the potential high-k dielectrics for replacing SiO2 as a gate dielectric. HfO2 is thermodynamically stable when in direct contact with Si and has a reasonable band gap (∼5.65eV). In this study, MOS capacitors (Pt/HfO2/Si) were fabricated by depositing HfO2 using reactive DC magnetron sputtering in the range of 33∼135Å followed by Pt deposition. During the HfO2 deposition, O2 flow was modulated to control interface quality and to suppress interfacial layer growing. By optimizing the HfO2 deposition process, equivalent oxide thickness (EOT) can be reduced down to ∼11.2 Å with the leakage current as low as 1X10−2 A/cm2 at +1.0V and negligible frequency dispersion. HfO2 films also show excellent breakdown characteristics and negligible hysteresis after high temperature annealing. From the high resolution TEM, there is a thin interfacial layer after annealing, suggesting a composite of Si-Hf-O with a dielectric constant of ≈ 2 X K SiO2.
Nanoindentation Study of Amorphous Metal Multilayered Thin Films
Authors: Vella J. B. , Cammarata R. C. , Weihs T. P. , Chien C. L. , Mann A. B. , Kung H. 
Published: April 2011

AbstractNanoindentation studies were preformed on amorphous metal, multilayered thin films containing alternating layers of Fe50Ti50 and Cu35Nb65 in order to investigate the mechanism for plastic deformation in metallic glass. Films with a total thickness of 1μm and bilayer repeat lengths ranging from 2 to 50 nm were magnetron sputter-deposited onto sapphire substrates. In contrast to many crystalline multilayered systems, where large hardness enhancements have been observed when the bilayer repeat length is reduced below about 10 nm, no significant hardness enhancement as a function of bilayer repeat length was observed in the Fe50Ti50/ Cu35Nb65 amorphous metal system. This result suggests that a dislocation–like mechanism for plastic deformation may not be appropriate for these amorphous metals.
Tribochemistry of ZDOL Decomposition on Carbon Overcoats in Ultra-High Vacuum (UHV)
Authors: Bhatia C. S. , Chen C.-Y. , Fong W. , Bogy D. B. 
Published: April 2011

AbstractTribochemical studies of the effect of lubricant bonding on the tribology of the head/disk interface (HDI) were conducted using hydrogenated (CHx) carbon disk samples coated with perfluoropolyether ZDOL lubricant. The studies involved drag tests with uncoated and carboncoated Al2O3-TiC sliders and also thermal desorption experiments in an ultra-high vacuum (UHV) tribochamber. We observed that a larger mobile lubricant portion significantly enhances the wear durability of the (head/disk interface) HDI by providing a reservoir to constantly replenish the lubricant displaced in the wear track during drag tests. In the thermal desorption tests we observed two distinct temperatures of desorption. The mobile ZDOL layer is desorbed at the lower thermal desorption temperature and the residual bonded ZDOL layer is desorbed at the higher thermal desorption temperature. We also observed that the hydrogen evolution from CHx overcoats initiates lubricant catalytic decomposition with uncoated Al2O3/TiC sliders, forming CF3 (69) and C2F5 (119). The generation of Hydroflouric acid (HF) during thermal desorption experiments provides the formation mechanism of Lewis acid, which is the necessary component for catalytic reaction causing Z-DOL lube degradation.
Fabrication and Characterization of Functionally Gradient Diamondlike Carbon Coatings
Authors: Wei Q. , Sharma A.K. , Yamolenko S. , Sankar J. , Narayan J. 
Published: April 2011

AbstractPure diamondlike carbon thin films largely bonded by four-fold coordination suffer from a large internal compressive stress that gives rise to a serious adhesion problem. In this work, functionally gradient (FG) diamondlike carbon thin coatings were prepared by pulsed laser deposition in a high vacuum chamber as an alternative approach to address the adhesion problem of diamondlike films. Copper, silver and titanium were incorporated into the growing films with their concentration as a function of the distance from the substrate surface. The top of the thin coating is pure DLC of about 400 nm in thickness. The total thickness of the functionally graded superhard DLC coatings can exceed 1.0 μm without buckling. Visible micro-Raman spectroscopy was used to characterize the bonding structure of the layers which contain alloy atoms. High resolution transmission electron microscopy was employed to study the microstructure of the coatings. Nanoscale mechanical characterizations using Nanoindenter XP™ were carried out to study the mechanical behavior of the functionally gradient DLC films.
A Brittle to Ductile Transition (BDT) in Adhered Thin Films
Authors: Gerberich W. W. , Volinsky A. A. , Tymiak N. I. , Moody N. R. 
Published: April 2011

AbstractIt has been long recognized that the BDT in bulk materials may be associated with enhanced plastic energy dissipation. This can be achieved by either changing the state of stress (plane strain to plane stress) or by raising the test temperature (lowering the yield stress). The situation is somewhat different in thin films where the BDT can be achieved by increasing film thickness or perhaps, even in a limited temperature range, by raising the test temperature. To study the latter we use a superlayer technique with a 1 μm tungsten film on top of thin copper films bonded to SiO2/Si wafers. This involves indenting into the superlayer which stores and then releases large amounts of elastic energy into the thin film/substrate interface. Here, preliminary data on 500 nm thick Cu demonstrates more than an order of magnitude increase in fracture energy from about 10 to 200 J/m2 as the test temperature is raised from 20°C to 130°C. As the amount of plastic energy absorption would appear to be limited by film thickness, this relatively large value was unanticipated. This interfacial fracture energy translates to a stress intensity of 5 MPa-m1/2. In context of the highest possible nanocrystalline Cu yield strength, this still represents a plastic zone of nearly 30 μm. This illustrates the quandary associated with explaining such high apparent toughness values as one generally expects plasticity to be truncated by film thickness. Is this associated with:–some artifact of assessing local stresses during nanoindentation at elevated temperature:–extending the plastic zone in the direction of crack growth much further than the film thickness;–a shielding mechanism from an organized dislocation array in a ductile film sandwiched between a brittle substrate and a higher yield strength superlayer;–some plastic energy dissipation in the superlayer;–or by enhanced mode II at higher temperatures?A few of these will be addressed in some detail with a goal of narrowing the field of the most promising candidates.
Modified Edge Lift-Off Test: Experimental Modifications for Multifilm Systems
Authors: Hay J. C. , Liniger E. G. , Liu X-H 
Published: April 2011

AbstractIn developing an adhesion test for a microelectronics fabrication facility there are many criteria which must be met. Some of these include (i) sample prep must be simple, (ii) deformations should be elastic so the problem can be easily modeled, (iii) mechanics are ideally analytical, and (iv) the test end-point must be unambiguous and easy to obtain. A testing method in the literature which meets many of these criteria is the modified edge liftoff test (MELT). Delamination is induced through the release of strain energy stored in an elastic superlayer which results from a large mismatch in CTE between the film and substrate. In this work we consider details of the energy release rate calculation, effects of plate bending, and initial flaw size.
Superlayer Residual Stress Effect on the Indentation Adhesion Measurements
Authors: Volinsky Alex A. , Moody Neville R. , Gerberich William W. 
Published: April 2011

AbstractThe practical work of adhesion has been measured in thin aluminum films as a function of film thickness and residual stress. These films were sputter deposited onto thermally oxidized silicon wafers followed by sputter deposition of a one micron thick W superlayer. The superlayer deposition parameters were controlled to produce either a compressive residual stress of 1 GPa or a tensile residual stress of 100 MPa. Nanoindentation testing was then used to induce delamination and a mechanics based model for circular blister formation was used to determine practical works of adhesion. The resulting measured works of adhesion for all films between 100 nm and 1 μm thick was 30 J/m2 regardless of superlayer stress. However, films with the compressively stressed superlayers produced larger blisters than films with tensile stressed superlayers. In addition, these films were susceptible to radial cracking producing a high variability in average adhesion values.
The Mechanical Properties of Common Interlevel Dielectric Films and Their Influences on Aluminum Interconnect Extrusions
Authors: Chen Fen , Li Baozhen , Sullivan Timothy D. , Gonzalez Clara L. , Muzzy Christopher D. , Lee H. K. , Levy Mark D. , Dashicll Michael W. , Kolodzcy James 
Published: April 2011

AbstractKnowledge of the mechanical properties of interlevel dielectric films and their impact on sub-micron interconnect reliability is becoming more and more important as critical dimensions in ULSI circuits are scaled down. For example, lateral aluminum (Al) extrusions into spaces between metal lines, which become a more of a concern as the pitches shrink, appear to depend partially on properties of SiO2 underlayers. In this paper, the mechanical properties of several common interlevel dielectric SiO2 films such as undoped silica glass using a silane (SiH4) precursor, undoped silica glass using a tetraethylorthosilicate (TEOS) precursor, phosphosilicate glass (PSG) deposited by plasma-enhanced chemical vapor deposition (PECVD) and borophosphosilicate glass (BPSG) deposited by sub-atmosphere chemical vapor deposition (SACVD) were studied. Among the four common interlevel layers, BPSG exhibits the smallest modulus (E), hardness (H) and the highest the coefficients of thermal expansion (CTE). BPSG again has the lowest as-deposited compressive stress and the lowest local Si-O-Si strain before annealing. Stress interactions between the various SiO2 underlayers and the Al metal film are further investigated. The impact of dielectric elastic properties on interconnect reliability during thermal cycles is proposed.
Electromigration Modeling of Blech Experiment with Comparison to Recent Experimental Data
Authors: Fan Zhineng , Korhonen M. A. , Li C.-Y. 
Published: April 2011

AbstractFinite element analysis is applied to simulate electromigration in a copper line/tungsten junction, which is a typical structure in Blech experiments adopted to measure the electromigration drift velocity by edge displacement. Because the specific resistivity of tungsten is higher than that of copper, the electric current crowds at the corner where the underlying tungsten bar connects to the edge of the copper line. Therefore, material in the corner is depleted faster than that in other places of the copper/tungsten interface. Our simulation reveals that a stress that may be high enough to crack the interface is also built up in the corner. The evolution of the line resistance under various current densities is calculated from our model and compared to recent experiment results.
The Implications of Energetic and Kinetic Surface Instability for a Stress Measurement Technique
Authors: Yu H. H. , Suo Z. 
Published: April 2011

AbstractIt has been understood for some time that elastic energy can cause surface roughening during a solid surface motion. This instability has recently led to a novel experimental technique to determine stress state on the surface of a solid by measuring the surface profile before and after etching [1]. Along a separate line of investigation, Aziz and co-workers has recently described a different kind of instability, also driven by stress [2]. Their experiments showed that the activation energy of the surface mobility depends linearly on the stress state, and this dependence can cause surface instability. The two kinds of instabilities have very different characteristics. In this paper, we describe a linear stability analysis of a three dimensional interface evolving under stress. The interface can be destabilized either by stress-dependent activation energy or by elastic energy. The implications for the stress measurement technique are discussed. It is suggested that the same experimental procedure be used to measure surface energy and activation strains.
The Strength and Fracture of Passive Oxide Films on Metals
Authors: Pang M. , Wilson D. E. , Bahr D. F. 
Published: April 2011

AbstractPassive films have been grown electrochemically on a polycrystalline titanium alloy. By varying the applied voltages, the film thickness is varied. A testing apparatus has been constructed to allow measurements of nanomechanical properties during electrochemical testing using a Ag/AgCl reference electrode in a traditional three-electrode potentiostatic scan. The stress at which oxide film fracture occurs is correlated to the applied potential. Observations of in situ film fracture measurements on single grains during immersion show the strength of the film remains constant in environments in which the film is inert, but decreases by approximately 20% in solutions which lead to corrosion. The fracture mode of the oxide has been observed using atomic force microscopy, and is shown to qualitatively match the largest tensile stresses which develop using elastic contact mechanics. A simplified model for determining the maximum tensile stress around an indentation is presented, and is used to show the stress required for fracture increases approximately linearly with increasing applied anodic polarization, from 850 MiPa to approximately 3 GPa for applied potentials between 1 and 9 V.