bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ebic Analysis of Gettering at Si-Si (Ge) Heteroepitaxial Misfit Dislocations as a Function of Impurity Decoration
Authors: Kirk H. R. , Radzimski Z. J. , Fitzgerald E. A. , Rozgonyi G. A. 
Published: September 2012

ABSTRACTAn EBIC analysis is made of decorated heteroepitaxial misfit dislocations formed at the interface of Si-Si (Ge) epitaxial layers grown in a CVD reactor on Si substrates. The electrical activity of the dislocations is studied after decorating the dislocations with Ni and Au impurities introduced by ion-implantation and backside deposited metallic thin films. The impurities are activated by RTA annealing at 400, 800 and 1000°C. A model is presented for the formation of NiSi2 precipitates on misfit dislocations which suggests that the nucleation and growth of NiSi2 precipitates is a function of the cleanliness of the as-grown dislocations. It is concluded that the distribution of electrical activity of impurity decorated misfit dislocations is a strong function of the impurity type, condition of the as-grown material, and concentration of metallic impurities introduced during the process of decoration.
Defect Analyses in VLSI Devices by TEM Observation and Process Simulation
Authors: Mikoshiba H. , Nishio N. , Matsumoto T. , Kikuchi H. , Kitano T. , Kaneko H. 
Published: September 2012

ABSTRACTThis paper presents several examples of defect analyses carried out in actual VLSI failure analyses and experiments, using TEM technique, process simulation and other advanced analytical tools. New TEM techniques are also described to observe a precise location which has failed.
Control of Process-Induced Defects in the Formation of Single and Multiple layer dielectric Structures for Si Semiconductor Devices
Authors: He S. S. , Stephens D. J. , Ma Y. , Yasuda T. , Habermahl S. , Lucovsky G. 
Published: September 2012

ABSTRACTA low-temperature, 200–300°C, plasma-assisted oxidation-deposition process sequence has been developed for formation of SiO2/Si heterostructures. Adding a nitride layer to form an ON, or ONO composite dielectric, increases the density of trapping states, Dit, at the SiO2/Si interface, unless the entire structure is subjected to a high-temperature rapid thermal anneal, e.g., 30 s at 900°C. By interrupting the nitride deposition, and using on-line Auger electron spectroscopy, AES, the increase in Dit correlates with a migration of N-atoms to the SiO2/Si interface during the nitride deposition. There is no evidence for N-atom incorporation into the oxide layer itself. In contrast, for remote PECVD deposition of oxides onto nitrides, O-atoms react with the nitride, and form an oxy-nitride alloy interfacial region layer.
The Influence of Thermal Treatment on Defect Characteristics in Cz-Silicon Wafers Investigated by Positron Annihilation Spectroscopy
Authors: Mascher P. , Puff W. , Hahn S. , Cno K. H. , Lee B. Y. 
Published: September 2012

ABSTRACTPositron lifetime and Doppler-broadening experiments as well as Fourier-transform infrared spectroscopy (FTIR) were performed on a variety of six-inch Czochralski (CZ) silicon wafers. Measurements were done at 14 equidistant locations across the wafers which were cut from the seed-, middle-, and tail-sections of two boules grown at different pull-speeds.In the as-grown wafers, the positron response consisted of components from small oxygen-related clusters and “perfect” bulk silicon only. Possible contributions from vacancy-type defects were at or just below the detection limit. After a two-step heat treatment (750°C/ 4 hrs + 1050°C/6 hrs in N2) FTIR showed that significant amounts of oxygen (4–8 ppma) had precipitated in wafers taken from the seed-sections of the boules but not in any of the other wafers. The positron data did not reflect this distinctive difference, however, both lifetime and Doppler-broadening results strongly indicate the creation of vacancy-type defects at concentrations in the 1016cm−3-range.
A Lifetime Study of Oxygen Agglomeration Induced Defects in Cz Silicon Crystal by Surface Photovoltage (SPV)
Authors: Mishra Kamal , Huber W. , Lagowski Jacek 
Published: September 2012

ABSTRACTIn this study the effect of oxygen agglomeration on minority carrier diffusion length in as-grown p-CZ silicon has been studied in detail. Oxygen-related defects were found acting as minority carrier traps in p-CZ silicon. These defects are not found in either oxygen-free FZ silicon or in n-type CZ silicon samples. The traps have profound effect on low excitation level diffusion length values leading to an apparent lifetime decrease by as much as an order of magnitude. This effect can be eliminated by a steady state “bias light” superimposed on the chopped excitation light. The traps can be annihilated and re-generated by thermal treatments.Our study has also revealed oxygen-induced recombination centers. Significant improvement in lifetime is realized in p-type CZ silicon after heat treatment between 550°C and 800°C.
Nucleation of Oxygen Precipitates in a Quenched Czochralski Silicon Crystal
Authors: Ikari A. , Haga H. , Yoda O. , Uedono A. , Ujihira Y. 
Published: September 2012

ABSTRACTWe have studied the nucleation of oxygen precipitates in Czochralski (Cz) Si crystal quenched from high temperature (1390°C). We observed that the oxygen precipitation was enhanced by the quenching treatment. We found the density of precipitates in the quenched crystal depended on quenching temperature and that nuclei for oxygen precipitates were introduced during quenching. We studied these nuclei using infrared absorption (IR) and positron annihilation techniques. In order to clarify the state of the nuclei, the quenched specimens were irradiated with 3-MeV electrons at a dose of 1×1018e/cm2and vacancy-oxygen complexes were introduced. Positron lifetime spectra and IR absorption spectra for these specimens were measured as a function of isochronal annealing temperature. From the annealing behavior of the vacancy-oxygen complexes, it was found that oxygen clusters are introduced by the quenching and these clusters are the nuclei for the enhanced precipitation of the quenched Si crystal.
Effects of Concurrent Co or Ti Silicidation on Transient Diffusion and End-of-Range Damage in Phosphorus Implanted Silicon
Authors: Honeycutt J.W. , Ravi J. , Rozgonyi G. A. 
Published: September 2012

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.
Defect Annihilation in Czochralski-Grown Silicon During Out-Diffusion Process Probed with Variable-Energy Positron Beam
Authors: Kitano T. , Wei L. , Tabuki Y. , Tanigawa S. , Mikoshiba H. 
Published: September 2012

ABSTRACTThe defect annihilation in CZ-crystal was first detected during the process of oxygen out-diffusion, by the positron measurements with a variable-energy beam. The defects, which were related to oxygen atoms such as oxygen cluster, were mainly annihilated at the high temperature, ex., 1150°C. The defect concentration was decreasing down to one tenth, compared with that for an as-grown crystal.
Effects of Fluorine on MOS Properties
Authors: Ma T. P. 
Published: September 2012

ABSTRACTThe incorporation of small amounts of fluorine has been found to improve the properties of MOS devices. In this paper, some of these results will be reviewed, several techniques to introduce fluorine will be described, the distributions of F resulting from these processes will be shown, and the possible mechanisms leading to the improved MOS device reliability will be discussed.
Depth Profiles of Thermal Donors in Czochralski-Grown N-Type Silicon
Authors: Tokuda Yutaka , Shimokata Toshihisa , Katayama Masayuki , Hattori Tadashi 
Published: September 2012

ABSTRACTDepth profiles of thermal donors introduced by heat treatment at 450°C in Czochralski-grown n-type silicon have been studied through capacitance-voltage measurements of Au Schottky diodes in the oxygen concentration range 8.1×1017 to 15.3×1017 cm3 Thermal donor concentrations increase with depth and their depth profiles are fitted to the error function equation. The obtained diffusivity decreases with annealing time and is higher for samples with the lower initial oxygen concentrations. Combining with the infrared absorption measurements, it is found that the curves of the diffusivity as a function of loss of interstitial oxygen coincide with each other. The similar tendency is observed on the oxygen diffusivity evaluated with secondary ion mass spectrometry. These results indicate that the oxygen diffusivity at 450°C is related to both the outdiffusion and clustering of oxygen. Depth profiles of thermal donors formed at 650°C are also reported.
Effects of Deliberate Metal Contamination on CCD Imagers
Authors: McColgin William C. , Lavine J. P. , Kyan J. , Nichols D. N. , Russell J. B. , Stancampiano C. V. 
Published: September 2012

ABSTRACTThe effects of intentional metal contamination on silicon charge-coupled device imagers are reported. Such imagers are both sensitive to and provide sensitive measures of the presence of metals in the fabrication process. High-purity iron, cobalt, nickel, copper, palladium, and gold were deliberately introduced into the device wafers just before the last high temperature step. Metals were found to cause both electrical defects and distinctive imaging defects.We find that transition metals can be effectively removed from device regions by internal gettering, but that this gettering can be defeated by a fast cool-down. Gold, however, is poorly gettered.
Some Possibilities of using Defects for Applications in Semiconductors
Authors: Lannoo Michel 
Published: September 2012

ABSTRACTSpecific situations where defects have a positive impact on the properties of semiconductors are examined. In a first category are ranged defects used as probes for characterizing materials. Then semiconductors with high concentration of defects like low temperature GaAs and porous Si are discussed. This is followed by cases where direct use is made of the defect properties (optical, pressure…). Finally several possibilities for defect engineering of materials are reviewed.
Drain Current DLTS Spectra and GaAs Substrate Crystal Effect on Low-Frequency-Oscillations of Si-Implanted Mesfets
Authors: Saito Yasuyuki , Suga Tohru , Inoue Kazuhiko , Mitani Tatsuro , Tomizawa Yutaka , Nishio Johji , Terashima Kazutaka , Katsumata Tohru , Fukuda Katsuyoshi , Washizuka Shoichi , Yashiro Satao , Tarami Shigeoki , Nakajima Masahiro , Watanabe Masayuki 
Published: September 2012

ABSTRACTWe report drain-current (Id) deep level transient spectroscopy (DLTS) spectra and liquid-encapsulated-Czochralski-technique (LEC) GaAs crystal effect on low-frequency-oscillation (LFO) of wide gate (400-μm) Si-implanted GaAs metal- semiconductor field- effect- transistors (MESFETs). In the range of this experiment we could not find distinguishing DLTS peaks surely to be linked with Id-LFO of the MESFETs. Stoichiometric-melt growth LEC-boules showed relatively large Id-LFO phenomena. As-rich-melt growth LEC-boules showed tolerance to Id-LFO. We conclude that Id-LFO is not directly linked to deep centers themselves but interaction between deep centers and potential profiles and electrons. Stability of potential profile or band profile depends on “pinning’ center, which affects Fermi-level or quasi-Fermi-level stability. ‘Pinning’ center such as EL2s of ‘LEC GaAs crystals” is essential.
Comparison of Current-Induced Migration of Be and C in GaAs/AlGaAs HBTs
Authors: Ren F. , Fullowan T. R. , Lothian J. R. , Wisk P. W. , Abernathy C. R. , Kopf R. F. , Emerson A. B. , Downey S. W. , Pearton S. J. 
Published: September 2012

ABSTRACTWe contrast the stability under bias-aging conditions of GaAs/AlGaAs HBTs utilizing highly Be- or C-doped base layers. Devices with Be doping display a rapid degradation of dc current gain and junction ideality factor. At 200°C, a 2 × 10 μm2 Be-doped device (4 × 1019cm−3 base doping) operated at a current density of 2.5 × 104 A. cm−2 shows a decrease in gain from 16 to 1.5 within 2h. Under the same conditions a C-doped device with even higher base-doping (7 × 1019 cm−3) is stable over periods of 36h, the longest time we tested our structures. The degradation of Be-doped devices is consistent with the mechanism of recombination-enhanced diffusion of interstitials into the adjoining layers. Similar results are obtained with Zn-doped devices. Since C occupies the As sub-lattice rather than the Ga sublattice as with Be and Zn, it is not susceptible to reaction with Ga interstitials injected during growth or bias-aging.
Dislocations as Sinks for Self-Interstitials in Gold Doped Float Zone Silicon
Authors: Mariani G. , Pichaud B. , Taylor W. J. , Yang W. -S. 
Published: September 2012

ABSTRACTSelf-interstitial sink efficiencies of dislocations γ were measured in gold doped FZ (111) and (100) samples, we found respectively γ=0.4–0.5 and γ=0.2–0.3. γ is probably sensitive to dislocation character and to the deformation process.
Vacancy Promoted Interdiffusion in Quantum Wells and Applications to Optoelectronic Devices
Authors: Ghisoni M. , Rivers A. W. , Lee K. , Parry G. , Zhang X. , Staton-Bevan A. , Pate M. , Hill G. , Button C. , Roberts J. S. 
Published: September 2012

ABSTRACTIn this paper we shall look at a technique, known as impurity free vacancy diffusion (IFVD) for selectively altering the optoelectronic response of quantum well material after growth with a view to monolithic device integration. We will discuss the mechanism, practical considerations and some possible applications.
Visible Luminescence from Silicon: Quantum Confinement or Siloxene?
Authors: Brandt M. S. , Fuchs H. D. , Höpner A. , Rosenbauer M. , Stutzmann M. , Weber J. , Cardona M. , Queisser H. J. 
Published: September 2012

ABSTRACTThe discovery of strong visible photoluminescence at room temperature from porous silicon has triggered new hope that light-emitting devices compatible with existing Si-technology might become possible. We first review the luminescence behavior observed in silicon-based materials such as amorphous Si, microcrystalline Si, or SiO2. We then critically discuss the present model for the luminescence from porous silicon based on quantum confinement in view of the growing experimental evidence for the importance of both hydrogen and oxygen to obtain efficient luminescence from this material. We propose an alternative explanation based on the presence of siloxene (SieO3H6) in porous silicon which is corroborated by experimental results obtained with photoluminescence, Raman and IR spectroscopy. An important aspect is that siloxene can be prepared by methods different from anodic oxidation, and one particular technique will be described together with possible ways to tune the luminescence energy.
A Consistent Model for Disordering of GaAs/AlAs- Superiattices During Zinc Diffusion
Authors: Zimmermann H. , Tan T. Y. , Goesele U. 
Published: September 2012

ABSTRACTA model for the disordering of GaAs/AlAs-superlattices during zinc diffusion, which is consistent with recently established models for gallium self-diffusion and zinc diffusion in GaAs, is presented. Four coupled partial differential equations resulting from the model are solved numerically. In accordance with measured data in the literature, no disordering without zinc can result for temperatures around 600°C. Zinc diffusion, however, produces a large amount of gallium self-interstitials, which leads to a complete disordering of superlattices with a period thickness of 32 nm to a depth of about 0.8 μm within one hour. The used values for the diffusion coefficient and the equilibrium concentration of gallium self-interstitials are a consistent splitting of the gallium interstitial dominated self-diffusion coefficient.
Electron Accumulation in AIGaSb/InAs Qw System, - Evidence for Coexistence of Deep Acceptor and Donor -
Authors: Ideshita S. , Furukawa A. , Mochizuki Y. , Mizuta M. 
Published: September 2012

ABSTRACTWe investigated the reason of the (imbalanced) accumulation of electrons in AIGaSb/lnAs/AIGaSb QW system in spite of the p-type conduction of undoped AIGaSb. It was found that the concentration of the accumulated electrons negligibly depended on the number of the interfaces, but increased linearly with the effective AlSb thickness. These results indicate that donor levels in AIGaSb are the dominant electron sources. We propose a model that the deep acceptors with larger concentration and donors coexist, and the electron accumulation depends on the energy position of the acceptor in AIGaSb with respect to the quantum level in the InAs well. Acceptor levels obtained experimentally are about 100 meV higher than the bottom of the InAs conduction band, and we succeeded in eliminating the electron accumulation by making the quantum level of the InAs well higher than this acceptor level. The origins of the donors and acceptors are also discussed.
Effect of Lt GaAs on Epitaxial Al/GaAs Schottky Diode Characteristics
Authors: Zhang Kai , Miller D. L. 
Published: September 2012

ABSTRACTThe effect of LT GaAs on the effective barrier height of the epitaxial Al/GaAs Schottky contact was investigated for the first time by inserting a thin LT GaAs layer (50 ∼ 500Å) between the in situ deposited Al film and conventional MBE GaAs epitaxial layer. The activation energy plot of saturation current for the devices showed that the effective barrier height exhibits a dependence on LT GaAs thickness and reaches a saturated barrier height when the LT GaAs layer exceeds a critical thickness. Compared to the samples which had no LT GaAs layer, the effective Schottky barrier height was decreased from 0.79 eV to 0.35 eV for the n-GaAs samples, and increased from 0.55 eV to 0.72 eV for the p-GaAs samples. The Schottky barrier height modification achieved by LT GaAs is tentatively explained in the terms of a bulk Fermi level pinning model. The work described here suggests that LT GaAs can be used as a defect source with controlled thickness to study defect associated phenomena such as Schottky barrier height modification.
Effects of Rapid Thermal Annealing on SiNx Capped MBE GaAs
Authors: Ito Akira , Usami Akira , Ueda Hiroyuki , Kano Hiroyuki , Wada Takao 
Published: September 2012

ABSTRACTEffects of rapid thermal annealing (RTA) with a SiNx encapsulant on molecular beam epitaxial GaAs are studied with deep level transient spectroscopy (DLTS) measurements and x-ray photoelectron spectroscopy (XPS) measurements. The RTA was performed at various temperatures form 800°C to 1100°C for 6sec. The electron trap EL2 is produced by the RTA above 850°C The EL2 depth profile produced after the RTA is fitted with a complementary error function. The SiNx cap layer is more effective to prevent the formation of the EL2 than the SiO* cap layer during the RTA, because the critical temperature of the SiNx cap where the EL2 concentration starts to increase is higher than that of the SiOx cap. Slight increase of the oxidized Ga atoms is observed after the RTA near the cap surface. The enhancement of the EL2 trap is discussed considering the outdiffusion of Ga atoms into the cap layer during the RTA.
The Diffusivtty-Mobility Ratio Under Strong Magnetic Field in Small Gap Superlattices with Graded Structures
Authors: Ghatak Kamakhya P. , De Badal 
Published: September 2012

ABSTRACTIn this paper we have studied the Einstein relation for the diffusivity-mobllity ratio (DMR) in small-gap superi at tices (SLS) with graded structures under magnetic quantization by formulating a new dispersion law. It is found, taking inAs/ GaSb SL as an example that the DMR increases in an oscillatory way with increasing carrier degeneracy due to SdH effect. The DMR in SL. is greater than that of the constituent materials. The theoretical results are in agreement with the suggested experimental method of determining the DMR in degenerate materials having arbitrary dispersion laws.
Relaxation-Induced Gettering of Metal Impurities in Silicon: Microscopic Properties of Effective Gettering Sites
Authors: Seibt M. 
Published: September 2012

ABSTRACTSome gettering processes like internal gettering or backside damage gettering base on heterogeneous precipitation of metal impurities at defects in pre-de ter mined parts of silicon wafers during cooling from high temperatures. We consider microscopic properties of effective heterogeneous nucleation sites for cobalt, nickel and copper impurities from the fundamental point of view of suicide precipitate formation. We follow the basic concept that such gettering sites are defects which allow fast precipitation, i.e. which remove kinetic limitations known from homogeneous precipitation of these impurities at small supersaturation. For Co and Ni it follows that distorted lattice sites in the core of dislocations may establish high incorporation rates of interstitial atoms into suicide particles, whereas for Cu sinks for silicon self-interstitials are suitable gettering sites.
Intrinsic Gettering of Iron in Czochralski Silicon Crystals
Authors: Aoki M. , Hara A. , Ohsawa A. 
Published: September 2012

ABSTRACTWe present a new experimental approach to studying the mechanism of intrinsic gettering of Fe in Czochralski silicon crystals. We present our experimental method and results for as-grown and intrinsic gettered wafers with high and low-level Fe surface contamination. We found that when annealing at the Fe supersaturation temperature, Fe concentration decreases faster in intrinsic gettered wafers than in as-grown wafers. Concentration saturated with annealing time for each sample and the saturated Fe concentration followed a simple Arrhenius relationship. Re-emission of Fe from the bulk defect region occurred above the gettering temperature. We conclude that in intrinsic gettering, Fe precipitates preferentially in the bulk defect region when the Fe impurities supersaturate as temperature drops.
Influence of Rapid Thermal Annealing on Recombination Properties of Polycrystalline Silicon
Authors: Kittler M. , Seifert W. 
Published: September 2012

ABSTRACTRapid thermal annealing was shown by EBIC to increase the minority-carrier diffusion length in cast polycrystalline silicon. The beneficial effect is due to a deactivation of intragrain defects (mainly dislocations) and is stable against post-RTA annealing up to at least 600 °C/ 10 min.