bluuebunny/crossref_metadata_2025_split huggingface dataset:
Defect Analysis of Rapid Thermal Processing Round Robin Results
Authors: Yarling C. B. , Keenan W.A. 
Published: March 2011

ABSTRACTThe Greater Silicon Valley Implant Users' Group (GSVIUG) has conducted a round robin to determine the uniformity and repeatability available in wafers processed with modern RTP equipment. High-dose ion implantation (As, 5E15, 80keV) of 150mm wafers was used to monitor temperature distribution through sheet resistance. Sheet resistance maps were then used to compare the uniformity and repeatability of each vendor. As previously reported, the actual uniformity results varied significantly with RTP vendor and implant conditions, ranging from 0.77% (one sigma/mean) to 3.55%. In addition, some contour patterns were quite representative of specific vendors.Subsequently, wafers from each participating vendor were evaluated by three techniques in order to determine what damage or defects might have resulted from the RTP process: laser flatness measurement, optical-imaging inspection, and thermal wave measurement. The flatness measurement system was used to measure the warpage of each sample. The reflective-optical inspection technique is a full-field, non-destructive technique that provides a real-time visual display, evidenced by light and dark field contrast over the entire wafer. The thermal wave measurement system uses two laser probes to measure a difference in modulated reflectance which results from damage or defects within the wafer.This paper describes each of the three techniques and summarizes the measured results of wafer defects and damage due to the processing by various RTP vendors. Comparisons between the three measurement techniques are made.
Pyrometric Emissivity Measurements and Compensation in an RTP Chamber
Authors: Nulman J. , Cohen B. , Blonigan W. , Antonio S. , Meinecke R. , Gat A. 
Published: March 2011

ABSTRACTThe emissivity effects and compensation schemes encountered in pyrometric temperature measurements in RTP systems are described in this paper. The emissivity effects include substrate roughness, layered films, substrate temperature, and chamber reflectivity. Compensation techniques are derived based on the emissivity effects, and include reference thermocouples and reflectance-based measurements. Compensated emissivity results in wafer-to-wafer temperature variations of less than ± 6 C, compared to as much as ± 100 C for uncompensated emissivity. A new model for emissivity analysis at temperatures larger than 700 C is also described.
Properties of Thin SiO2 Films with In-Situ Deposition of Poly Si Electrodes
Authors: Pan Paihung , Kermani Ahmad , Berry Wayne , Liao Jimmy 
Published: March 2011

ABSTRACTElectrical properties of thin (12 nm) SiO2 films with and without in-situ deposited poly Si electrodes have been studied. Thin SiO2 films were grown by the rapid thermal oxidation (RTO) process and the poly Si films were deposited by the rapid thermal chemical vapor deposition (RTCVD) technique at 675°C and 800°C. Good electrical properties were observed for SiO2 films with thin in-situ poly Si deposition; the flatband voltage was ∼ -0.86 V, the interface state density was < 2 × 1010/cm2/eV, and breakdown strength was > 10 MV/cm. The properties of RTCVD poly Si were also studied. The grain size was 10-60 rim before anneal and was 50-120 rim after anneal. Voids were found in thin (< 70 nm) RTCVD poly Si films. No difference in either SiO2 properties or poly Si properties was observed for poly Si films deposited at different temperatures.
Crystal Stability and Microstructural Evolution in Polycrystalline Si Films During Ion Irradiation
Authors: Atwater Harry A. , Brown Walter L. 
Published: March 2011

AbstractAmorphous Si is nucleated heterogeneously at grain boundaries during irradiation of polycrystalline Si by 1.5 MeV Xe+ ions for temperatures of 150–225°C. Following formation at grain boundaries, the amorphous Si layer grows at a rate comparable to the growth rate of a pre-existing amorphous-crystal interface, resulting in a decrease in average grain size and a marked change in the grain size distribution. The heterogeneous nucleation kinetics of amorphous Si are strongly dependent on grain boundary structure. A simple atomistic model for amorphous phase formation, which suggests that the nucleation kinetics are dependent on the point defect mobilities and grain boundary structure, is related to the experimental results.
In-Situ Reflectance Measurements of Measurements of During Ion Implantation
Authors: Swart Pieter L. , Lacquet Bea M. , Grobler Michael F. 
Published: March 2011

AbstractDamage introduced during ion implantation of semiconductor materials coalesce at a certain critical dose, for a particular energy and ion species. After this threshold dose rapid changes occur in the reflectance. This may be used for studying the amorphization process, or it may be applied as a non--destructive dosimeter and uniformity tool.An automated reflectometer was developed for studying reflectance during ion implantation of semiconductors with various ion species. Results on argon and phosphorous implants into silicon at energies ranging from 50 to 240 keV are presented.
Is the End-of-Range Loops Kinetics Affected by Surface Proximity or Ion Beam Recoils Distribution?
Authors: Ganin E. , Marwick A. 
Published: March 2011

AbstractWe studied formation and annihilation of dislocation loops formed beyond the amorphous/crystalline interface after indium and boron dual implantation and subsequent annealing in the 800–1 100°C temperature range. The residual damage for low (40 keV) and high (200 keV) energy In implants were compared. The depth of the amorphous region in the sample implanted with the higher energy ions was reduced by using anodic oxidation and etching, to equate it with that of the sample implanted by lower energy ions. This enabled the study of the effect of surface proximity on residual disorder upon annealing. The damage was strongly dependent on the energy of In ions. No end-of-range damage was observed for the low energy implant. High energy implantation resulted in end-of-range dislocation loops, stable below 1050°C. The loops kinetics was neither affected by their proximity to the surface, nor by In precipitation. Monte-Carlo full cascade simulation has been used to estimate the depth distribution of interstitials and vacancies produced by In implant.
Lattice Defects Generated by Ion Implantation into Submicron Si Areas
Authors: Tamura M. , Shukuri S. , Kawamoto Y. 
Published: March 2011

AbstractCross-sectional transmission electron microscopy observations have been carried out to clarify two-dimensional depth distributions of lattice defects generated in high-dose (5 x 1015 ions/cm2 ), P, As, BF2 and B implanted, annealed submicron Si areas as a function of implantation areas. Monte Carlo simulation is also adapted for ion-implantation into submicron Si through fine mask patterns to predict the effect of mask size on spatial damage and impurity profiles. Simulation results predict that the above profiles have a strong mask size dependence for regions below the critical size, where the dopant concentration decreases and damage depth moves toward the surface-side with a reduced implantation area. Some experimental results support simulation results, although most defects, mainly in the P and As implantation, are confined within the original amorphized layers, independent of mask size. However, in BF2 and B implantation, unexpected defect behavior such as variations in defect distribution from one implanted layer to another is found to occur in submicron regions doped by implantation.
MeV Implantation of Gallium Arsenide
Authors: Kanber H. , Chen J. C. , Barger M. J. 
Published: March 2011

AbstractWe investigated n-type MeV implants into semi-insulating GaAs to fabricate fully implanted varactor diodes for monolithic millimeter-wave applications. Single and multiple implants of Si from 6 to 2.5 MeV and 6 MeV S implants in GaAs were studied before and after capless furnace annealing and rapid thermal annealing by chemical profiling using secondary ion mass spectrometry (SIMS) and electrochemical and traditional differential capacitance-voltage profiling. A buried active layer at a depth of 2.8 μ.m with a peak carrier concentration of 2.5 × 1018 cm-3 was achieved by using 6 MeV Si + 4 MeV Si + 6 MeV S implants and rapid thermal annealing them at a temperature 1050°C for 10 seconds. The chemical profiles are correlated to the electrical profiles to determine activation and annealing behavior of MeV Si and Simplants in semi-insulating GaAs.
Influence of the Temperature of Implantation on the Morphology of Defects in MeV Implanted GaAs.
Authors: Braunstein G. , Chen Samuel , Lee S.-Tong , Rajeswaran. G. 
Published: March 2011

AbstractWe have studied the influence of the temperature of implantation on the morphology of the defects created during 1-MeV implantation of Si into GaAs, using RBS-channeling and TEM. The annealing behavior of the disorder has also been investigated.Implantation at liquid-nitrogen temperature results in the amorphization of the implanted sample for doses of 2×1014 cm−2 and larger. Subsequent rapid thermal annealing at 900°C for 10 seconds leads to partial epitaxial regrowth of the amorphous layer. Depending on the implantation dose, the regrowth can proceed from both the front and back ends of the amorphous region or only from the deep end of the implanted zone. Nucleation and growth of a polycrystalline phase occurs concurrently, limiting the extent of the epitaxial regrowth. After implantation at room temperature and above, two distinct types of residual defects are observed or inferred: point defect complexes and dislocation loops. Most of the point defects disappear after rapid thermal annealing at temperatures ≥ 700°C. The effect of annealing on the dislocation loops depends on the distance from the surface of the sample. Those in the near surface region disappear upon rapid thermal annealing at 700°C, whereas the loops located deeper in the sample grow in size and begin to anneal out only at temperatures in excess of 900°C. Implantation at temperatures of 200 - 300°C results in a large reduction in the number of residual point defects. Subsequent annealing at 900°C leads to a nearly defect-free surface region and, underneath that, a buried band of partial dislocation loops similar to those observed in the samples implanted at room temperature and subsequently annealed.
Oxygen Doped Silicon Surface Layers by Ion Implantation
Authors: Srikanth K. , Ashok S. 
Published: March 2011

AbstractOxygen doping of silicon with ion implantation has been attempted with the aim of modifying the surface electrical properties of the substrate. The change in currentvoltage (I–V) characteristics after 1200 °C anneal has been ascribed to the formation of Oxygen Doped Silicon. The independence of the I–V characteristics on the choice of top metal contact and the reversal in direction of rectification strongly suggest the formation of an alloy layer in Si by the implantation. SIMS measurements indicate a sharp oxygen profile after the anneal and FTIR data show that oxygen is in the form of SiO2 embedded in a silicon matrix.
Ion Implantation Processing of Gaas and Related Compounds
Authors: Pearton S. J. , Hobson W. S. , Abernathy C. R. 
Published: March 2011

AbstractThe formation of doped or semi-insulating layers by ion implantation in both Ga- and In- based semiconductors is reviewed. The Ga-based materials (GaAs, AIGaAs, GaP, GaSb) tend to show similar characteristics in terms of producing relatively low (n ≤ 3 × 1018 cm-3) maximum carrier densities for donor implanted layers, and much higher values for acceptor implants (p ≤ 5 × 1019 cm-3 ). Ion-induced damage is widely used for device isolation in these materials, with midgap levels associated with the damage trapping free carriers and leading to semi-insulating behaviour. By contrast, the In-based materials (InP, InAs, InSb and InGaAs) show higher maximum carrier densities for acceptor implants than for donor implants, and the use of ion damage for isolation purposes is much less effective than in GaAs. All of these materials display singularly poor regrowth characteristics, requiring in some cases the use of elevated temperature implantation to prevent amorphization
Shallow Doping of Gallium Arsenide by Recoil Implantation
Authors: Sadana D. K. , de Souza J. P. , Rutz R. F. , Cardone F. , Norcott M. H. 
Published: March 2011

AbstractSi atoms were recoil-implanted into GaAs by bombarding neutral (As+) or dopant (Si+) ions through a thin Si cap. The bombarded samples were subsequently rapid thermally or furnace annealed at 815–1000°C in Ar or arsine ambient. The presence of the recoiled Si in GaAs and resulting ni-doping was confirmed by secondary ion mass spectrometry and Hall measurements. It was found that sheet resistances of < 150 Ω/‪ can be achieved by this method. Capless furnace annealing in arsine ambient generally yielded better electrical results (especially for shallow implants, i.e., < 100 nm deep) compared to those obtained by RTA in an inert ambient with a Si cap. In the latter case, electrical activation deteriorated above 900°C due to high As loss and the deterioration was pronounced for shallow implants. Significant Si redistribution occurred during arsine annealing whenever the Si concentration (from recoil or direct implant) in GaAs exceeded 1×1019cm3 and the annealing temperature was > 850°C. Our present electrical data show that the recoil implant method is a viable alternative to direct shallow implant for n+ doping of GaAs.
Molecular Ion S2+ and SiFn+ implantations into GaAs
Authors: Fan W. D. , Wang W. Y. 
Published: March 2011

AbstractMolecular ion S2+ and SiFn+ implantations into GaAs have been investigated to form very thin active layers. After implantation, the transient annealing (TA) and furnace annealing (FA) were used. The measurements of activation efficiency, mobility, carrier concentration profiles and PL spectra were carried out. The experiments show that after TA, the activation efficiency, mobility and carrier distribution are almost the same between samples implanted with S+ at an energy of 50KeV to a dose of 3×1013cm−2 and S+2 at 100KeV to 1.5×1013cm−2. It shows that the damage of S2-implanted samples can be removed by TA, and a very thin active layer can be formed by the implantation of S2+ at 50KeV. For SiFn-implanted samples, the activation efficiency and mobility. decrease with increase of the implanted ion mass. As+ co-implantation into SiF-implanted samples has been used to improve both activation efficiency and mobility. After comparison with the properties of the SiFt implantation, S2+implantation is more acceptable to form thin active layers.
Dual Ion Implantations of Si+As and S+As into GaAs
Authors: Fan W. D. , Wang W. Y. , Zhou B. L. 
Published: March 2011

AbstractAs+ implantation has been used to compensate the As loss during annealing for Si- or S-implanted GaAs. The As+ implantation was at an energy range of 25–100KeV to a dose range of 1012-1015cm−2. The Si+ or S+ implantation was at 150 or 50KeV respectively to the same dose, 27times;1013cm−2. By using the measurements of the Hall effect and sheet resistivity, the activation efficiency and mobility of the dually implanted sample with Si+ and As+ (25KeV, 1×1013cm− 2 ) after TA at 1050°C for 6s increase by 21 and 18% respectively over those of the singly Si-implanted sample after TA at 1100°C for 6s. Those of the dually implanted sample with Si+ and As+ (100KeV, 1×1013cm− 2 ) increase by 63 and 30% respectively over those of the singly Si-implanted sample after FA at 800°C for 30min. Also, the density of SiAs and VGa determined by 20K PL spectra decreases of dually Si- and As-implanted samples. The activation efficiency and mobility of the d8ally implanted sample with S+ and As+ (40KeV, 1×1013cm−2 ) after TA at 1100°C for 12s increase by 17 and 16% respectively over those of the singly Simplanted sample. The annealing behaviour after As+ implantation is discussed.
Ultra-Pure Processing: a Key Challenge for Ion Implantation Processing for Fabrication of ULSI Devices
Authors: Current M. I. , Larson L. A. 
Published: March 2011

AbstractA key issue in modern ion implantation processing is the requirement for dramatic improvements in the purity of the incident ion beam and reductions in the deposition of foreign materials onto the wafer surface. These deposited materials include particles as well as sputtered and vapor deposited metals and dopants. Physical mechanisms which effect the elemental purity of atoms arriving at the surface of ion implanted wafers and progress towards achieving implantation purity levels of below 100 ppm of the implanted dose for sputtered metal and dopant films are discussed.
Electronic Properties of Ion Implanted Polymer Films
Authors: Giedd R. E. , Shipman J. , Murphy M. 
Published: March 2011

AbstractWe have implanted a number of insulating polymer (PET) thick films with fluences in the range 1 × 1013 to 5 × 1017 ions/cm2 in order to induce electronic activity. Finite electrical conductivities were obtained for fluences as low as 3 × 10 15ions/cm2. The resistivity for these implanted materials increases with decreasing temperature demonstrating highly disordered or semiconducting behavior. Hall effect measurements confirm this result and indicate negatively charged carriers with a carrier density of 1.44 × 10 17cm -3 for an implant dose of 1 × 1017 ions/cm2. The conductivities also seem to be dependent on the implanted ion species. We believe this material will be useful as an accurate temperature sensor near room temperature.
Ion Beam Modification of the Y-Ba-Cu-O System with the Mevva High Current Metal Ion Source
Authors: Brown I. G. , Rubin M. D. , Yu K. M. , Mutikainen R. , Cheung N. W. 
Published: March 2011

AbstractWe have used high-dose metal ion implantation to ‘fine tune’ the composition of Y-Ba- Cu-O thin films. The films were prepared by either of two rf sputtering systems. One system uses three modified Varian S-guns capable of sputtering various metal powder targets; the other uses reactive rf magnetron sputtering from a single mixed-oxide stoichiometric solid target. Film thickness was typically in the range 2000–5000 A. Substrates of magnesium oxide, zirconia-buffered silicon, and strontium titanate have been used. Ion implantation was carried out using a metal vapor vacuum arc (MEVVA) high current metal ion source. Beam energy was 100–200 keV, average beam current about 1 mA, and dose up to about 1017 ions/cm2. Samples were annealed at 800 – 900°C in wet oxygen. Film composition was determined using Rutherford Backscattering Spectrometry (RBS), and the resistivity versus temperature curves were obtained using a four-point probe method. We find that the zero-resistance temperature can be greatly increased after implantation and reannealing, and that the ion beam modification technique described here provides a powerful means for optimizing the thin film superconducting properties.
Lattice Strain from Holes in Heavily Doped Si:Ga
Authors: Kavanagh K. L. , Cargill G. S. , Boehme R. F. , Chang J. C. P. 
Published: March 2011

AbstractHeavily doped Si:Ga has been prepared by liquid phase epitaxy (LPE) and by ionimplantation with rapid thermal annealing (RTA) or laser annealing (LA). Peak substitutional Ga concentrations obtained by each technique were 1.5, 2.5 and 2.9 ×1020cm-3, respectively. Substitutional fractions (>90%) were similar in the three types of samples, and the conductivity scaled with the total Ga concentration. A lattice expansion per substitutional Ga atom in Si of +0.9 ± 0. l×10-24cm3 /atom was measured by double crystal x-ray diffraction. The average nearest neighbor Si-Ga bond length measured with extended x-ray absorption fine structure (EXAFS) was 0.237 ± 0.004 nm, indistinguishable, to within experimental error, from the intrinsic Si-Si bond lngth, 0.235 nm. Combining these two results the lattice strain per hole in the Si valence band was calculated, +0.4 ± 0.8x10G-cm3. This result complements the lattice contraction per electron in the Si conduction band (-1.8 ± 0.4x10-24cm 3) already reported for Si:As [G. S. Cargill III, J. Angilelloand K. L. Kavanagh, Phys. Rev. Letters 61, 1748 (1988)].
Reduction of Excess Self-Interstitials in Silicon by Germanium and Silicon Implantation-Induced Damage
Authors: Fahey Paul 
Published: March 2011

AbstractWe have investigated a phenomena first reported by Pfiester and Griffin, that the presence of implanted Ge in Si can substantially reduce excess self-interstitial concentrations [ J. R. Pfiester and P. B. Griffin, Appl. Phys. Lett., 52, 471 (1988) ]. By studying the effects of Ge implantation on P diffusion, we are able to deduce that residual implantation damage can act as an efficient sink for self-interstitials. This effect can also be produced by Si self-implantation, demonstrating that there is nothing unique about the chemical indentity of Ge in reducing self-interstitial concentrations. Our experiments provide solid evidence that there is no unexpectedly strong interaction of Ge with self-interstitials, a situation that would undermine the validity of previous Ge diffusion experiments aimed at studying Si self-diffusion. Our experimental results show that the effect of Ge implantation on P diffusion is a complicated function of implantation conditions. Diffusion is affected by the order of thl P and Ge implants as well as by changes in implant energies and doses.
Temperature Dependence of Damage in Boron-Implanted Silicon
Authors: Ottaviani G. , Nava F. , Tonini R. , Frabboni S. , Cerofolini G. F. , Cantoni P. 
Published: March 2011

AbstractWe have performed a systematic investigation of boron implantation at 30 keV into <100> n-type silicon in the 77 –300 K temperature range and mostly at 9×1015 cm−2 fluence. The analyses have been performed with ion channeling and cross sectional transmission electron microscopy both in as-implanted samples and in samples annealed in vacuum furnace at 500 °C and 850 °C for 30 min. We confirm the impossibility of amorphization at room temperature and the presence of residual damage mainly located at the boron projected range. On the contrary, a continuous amorphous layer can be obtained for implants at 77 K and 193 K; the thickness of the implanted layer is increased by lowering the temperature, at the same time the amorphous-crystalline interface becomes sharper. Sheet resistance measurements performed after isochronal annealing shows an apparent reverse annealing of the dopant only in the sample implanted at 273 K. The striking differences between light and heavy ions observed at room temperature implantation disappears at 77 K and full recovery with no residual damage of the amorphous layer is observed.
In-Situannealing Transmission Electron Microscopy(Tem) Study of the Ti/GaAs Interfacial Reactions
Authors: Kim Ki-Bum , Sinclair Robert 
Published: March 2011

ABSTRACTIn-situ annealing TEM experiments were performed on the Ti/GaAs system in order to study the dynamic behavior of interfacial reactions. Both plan-view and cross-sectional samples were investigated in either diffraction and imaging (both conventional and high resolution) modes. During experiments, we observed the following: (a) At the initial stage of reaction, the TiAs phase formed at the original Ti/GaAs interface with a distinct orientation with respect to the substrate; (b) as the reaction proceeded, the TiAs phase formed in a random manner; (c) finally, the liberated Ga species from the GaAs diffused out to the metal film and formed TiGa2 phase in the plan-view sample similar to the furnace-annealed case. For the cross-sectional sample, however, we did not observe any Ti:Ga phase formation. Instead, we observed the formation of voids both in the Ti film and in the GaAs substrate. The formation of different microstructure between in-situ and furnace annealed cases is explained by the sample geometry during annealing.