bluuebunny/crossref_metadata_2025_split huggingface dataset:
Excitation Spectroscopy of the Defect Bound Excitons in MBE GaAs
Authors: Charbonneau S. , Mcmullan W. G. , Henry M. O. , Thewalt M. L. W. 
Published: March 2011

ABSTRACTThe origin of the complex photoluminescence line series often observed in MBE-grown GaAs has been the subject of considerable recent study. We report on the results of high resolution, high sensitivity resonant excitation measurements which conclusively prove the lines to result from the recombination of excitons bound to a series of acceptors. New details of the properties of the bound excitons and acceptors are revealed. The direct connection between this acceptor series and an often-observed series of broader, lower energy lines is also established. Some preliminary studies of this line series under applied magnetic fields are also described.
Optically Detected Magnetic Resonance of Donors in AlxGa1−x as with High AlAs Fraction
Authors: Kennedy T. A. , Magno R. , Glaser E. , Spencer M. G. 
Published: March 2011

ABSTRACTOptical and magnetic properties of donors in high AlAs-fraction AlxGa1−x As have been determined using optically-detected magnetic resonance. Many samples exhibit a sharp resonance at g = 1.95 detected on midgap luminescence. One high-quality sample exhibits an exhange-broadened line which reveals a distribution in donor-acceptor pair separations on moderately deep emission. A second high-quality sample exhibits the donor ODMR on donor-to-shallow- acceptor photoluminescence.
Lattice Relaxation of the DX Centers in Ga1−x Alx As and of the Pressure–Induced Deep Donors in GaAs
Authors: Li M. F. , Shan W. , Yu P. Y. , Ransen W. L. , Weber E. R. , Bauser E. 
Published: March 2011

ABSTRACTDeep Level Transient Spectroscopies (DLTS) and capacitance transient techniques have been applied to GaAs:Si and to Ga1−xAlxAs:Te (x=0.35) under quasi-hydrostatic pressure using a diamond anvil cell. By substituting the experimental pressure coefficients of the defect energies into a model proposed by Li and Yu (Solid State Commun. 61, 13 (1987)) we concluded that both the DX center in the GaAlAs alloy and the pressure-induced deep donor (PIDD) in GaAs have large lattice relaxations associated with them.
Tem Investigation of Strain Relaxation in ZnSe/ZnSxSe1−x Superlattices Grown by MBE
Authors: Petruzzello J. , Boser O. , Kellawon P. 
Published: March 2011

ABSTRACTThe relaxation mechanisms of ZnSe/ZnSxSe1−x superlattices grown by molecular beam epitaxy was studied by transmission rAeclmn icroscopy. The relaxation of misfit strain occured in part by conventional misfit dislocations that reside in the superlattice-buffer layer interface and in part by dislocations pinned at individual layer interfaces of the superlattice. The generation of misfit dislocations at the superlattice-buffer layer interface is inhibited by the misfit strain between individual superlattice layers. Therefore a significant amount of overall strain is present even after 1 μm of growth. Because misfit dislocations are not sufficient in relief of the misfit strain cracks are able to propagate
A Molecular Rebonding Bistable Defect in Silicon: the Interstitial Carbon-Substitutional Carbon Pair
Authors: Song L. W. , Zhan X. D. , Benson B. W. , Watkins G. D. 
Published: March 2011

ABSTRACTA new type of bistable center is observed in electron-irradiated Si and identified as an interstitial carbon-substitutional carbon pair by combining several spectroscopic techniques. In the positive and negative charge states, the stable configuration of the defect involves a carbon-silicon interstitialcy (each atom 3-fold coordinated) next to a 4-fold coordinated substitutional C atom. In the neutral state, the defect rearranges its bonds so that both C atoms are substitutional (4-fold coordinated) with a 2- fold coordinated Si atom nestled between. Configurational coordinate energy surfaces are determined for each of the three charge states.
The Diffusivity of Self-Interstitials in Silicon
Authors: Morehead Frederick F. 
Published: March 2011

ABSTRACTValues of the diffusivity of silicon self-interstitials have been previously inferred from analyses of the in-diffusion of Au in undislocated Si, e.g., 2×10-7 cm2 s-1 at 1100 °C. A more complete analysis by numerical integration of the effective diffusion equation with fewer assumptions yields ahigher minimum value, 6×10-6 cm2s-1 at 1100 °C. Recently published experiments showing no measurable difference in the oxidation-reduced diffusion of Sb in Si at 10 and 40 microns are consistent with this high value.
The Structure of the (001)Si/SiO2 Interface
Authors: Ourmazd A. , Bevk J. 
Published: March 2011

AbstractWe show that a careful examination of previous microscopic structural data from the Si/SiO2 interface reveals that the presence of an epitaxial interfacial oxide cannot be ruled out, and describe the conditions necessary for a definitive search for an intervening layer between c-Si and a-SiO2 We present electron diffraction and lattice imaging data, which establish the c-Si→a-SiO2 transition to take place via a crystalline layer ˜7 A thick. Modelling of lattice images in two projections indicates the crystalline oxide to be tridymite, a stable, bulk phase of SiO2
Defect Microchemistry at the SiO2/Si Interface
Authors: Rubloff Gary W. 
Published: March 2011

AbstractA dominant, intrinsic chemical reaction path in SiO2/Si systems is the decomposition reaction Si +SiO2 → 2 SiO. Controlled analytical studies have elucidated the microchemical and microstructural aspects of this process and revealed that nucleation of the reaction occurs at existing defect sites. At an earlier stage of reaction, the same decomposition chemistry leads to electricl activation of the defects, as seen in breakdown and hole trapping phenomena. By careful and systematic control of ambient conditions during annealing, it is shown that the evolution of electrically active defects follows the same decomposition chemistry as does the physical deterioration of an entire oxide layer. These aspects of defect chemical behavior suggest implications for both defect identification and defect control in thin SiO2 layers on Si.
Electrical, Optical and Structural Properties of Thin SiO2 Films On Si
Authors: Ravindra N. M. , Russo O. L. , Fathy D. , Narayan J. , Heyd A. R. , Vedam K. 
Published: March 2011

AbstractBreakdown voltage, static current-voltage, spectroscopic ellipsometry (SE), electrolyte electroreflectance (EER) and high resolution transmission electron microscopic (HRTEM) studies of thermally grown thin films of SiO2 on silicon (800°C - dry) are reported here. The investigation of the electrical properties of these films lead us to suggest the criteria for determining the breakdown voltage of these 20nm thick SiO2 films. The Fowler-Nordheim tunneling contribution to current conduction mechanisms in SiO2 has been considered in evaluating these criteria. SE, EER & HRTEM studies have been performed on SiO2 films of thicknesses in the range of 1–20 nm. These studies lead us to determine the thickness of the non-stoichiometric silicon-rich oxide existing at the Si-SiO2 interface. EER studies show that the relative surface state densities for different film thicknesses can be determined. The role of the transition region in determining the dielectric strength of thin SiO2 films is discussed.
Measurement of Optical Absorption in Very Thin Low-Loss SiO2 Films
Authors: Curran Robert M. , Crook Thomas M. , Zook J. David 
Published: March 2011

AbstractWhile low levels of optical absorption are easily measured in SiO2 bulk samples or optical fibers, we present here a method of detirmining low levels of absorption in thin films of SiO2. Films are deposited on top of high reflectivity multi-layer miriors, and absorption is derived from the time decay in a resonant cavity of threj mirrorsgt 633 nm. Absorption coefficients on the order of 1 cm−1. (k = 10−5) can be measured in films as thin as 100 Angstroms.With this method, we find that absorption at 633 nm can be induced in SiO2 films by exposing them to a He-Ne plasma discharge. Although the plasma radiation (>10 eV) is absorbed near the SiO2 surface, the plasma-induced absorption is uniform within the SiO2 film. This was shown by plasma irradiation of SiO2 films of 4arying thickness, together with computer calgulation of the optical properties of multilayer thin films. Similar absorption behavior has been reported in SiO2 optical fibers and may be due here to DIA (Drawing-Induced Aisorption) centers or NBOHCs (Non-Bridging Oxygen Hole Centers).
Enhanced Conduction In Sipos Films With High Oxygen Content
Authors: Chang K.-T. , Lam C. , Rose K. 
Published: March 2011

AbstractPolysilicon films with high oxygen content (SIPOS) have been prepared by LPCVD. These films have a two-phase structure with silicon crystallites surrounded by amorphous oxide, as confirmed by TEM and HRTEM measurements. Increasing the ratio of nitrous oxide to silane, R, during growth allows us to vary the oxygen concentration. Contrary to expectation, we observe a region where conduction increases as R is increased from 1 to 10. This can be accounted for by deviations from monotonicity in the dependence of silicon volume fraction on R. We also observe some influence of the SIPOS/silicon interface on conduction.
The Effect of Ge Segregation on Oxidation of Si
Authors: Frey E. C. , Parikh N. R. , Swanson M. L. , Numan M. Z. , Chu W. K. 
Published: March 2011

AbstractWe have studied oxidation of various Si samples including: Ge implanted Si, CVD and MBE grown Si(0.4–4% Ge) alloys, and MBE grown Si-Si(Ge) superlattices. The samples were oxidized in pyrogenic steam (800–1000°C, atmospheric pressure) and at low temperature and high pressure (740°C, 205 atm of dry O2). The oxidized samples were analyzed with RBS/channeling and ellipsometry.An enhanced oxidation rate was seen for all Ge doped samples, compared with rates for pure Si. The magnitude of the enhancement increased with decreasing oxidation temperature. For steam oxidations the Ge was segregated from the oxide and formed an epitaxial layer at the Si-SiO2 interface; the quality of the epitaxy was highest for the highest oxidation temperatures. For high pressure oxidation the Ge was trapped in the oxide and the greatest enhancement in oxidation rate (>100%) was observed.
Physical and Chemical Properties of Silicon Dioxide Film Deposited by New Process
Authors: Goda Takuji , Nagayama Hirotsugu , Hishinuma Akihiro , Kawahara Hideo 
Published: March 2011

AbstractA new coating process of silicon dioxide (SiO2) “LPD” process, has been developed recently. Silicon dioxide (SiO2) film can be deposited on any substrate at the room temperature by immersing in hexafluorosilicic acid (H2SiF6).In this study, physical and chemical properties of the “LPD- SiO2” film were investigated by using XPS, IR, ellipsometry, and etch rate measurement. The properties of this film deposited at the room temperature were almost the same as those of plasma CVD. The “LPD-SiO2” film without annealing was contained traces of F and OH. However, by annealing, F and OH were rapidly evaporated from the film and the film was getting densified.As the “LPD-SiO2” film deposited at the room temperature showed very good results of chemical etching rate and of step coverage, it is expected that it is possible to use this “LPD- SiO2” film in the wide range of industrial area.
Film Growth Mechanism of Photo-Chemical Vapor Deposition
Authors: Inushima T. , Hirose N. , Urata K. , Ito K. , Yamazaki S. 
Published: March 2011

AbstractThe photo-chemical vapor deposition (CVD) of SiO2 and SiN2 were investigated using 185 nm light of a low pressure mercury lamp. The film thickness deposited on the substrate was the function of the distance from the substrate to the light source and its relation was investigated by changing the reaction pressure. From these investigations, the space migration length of the active species was estimated, which was, at the processing pressure of 400 Pa, about 10–20 mm. This migration length was confirmed by a model calculation. The step coverage of the film was investigated by the use of a two-dimensional capillary cavity. It was shown that the thickness decayed exponentially with the depth in the cavity. The decay constant did not show temperature dependence. From this result, the surface migration of the active species produced by photo-CVD was reported. To confirm this migration we presented a substrate- size effect of photo-CVD, which became obvious when the substrate size became smaller than the space migration length of the active species. From these results, the film growth mechanism of photo-CVD was discussed.
Study of SiO2 Formation by Plasma Treatment of SiO Thin Films
Authors: Perriere J. , Pelloie B. , Rochet F. , Fogarassy E. , Slaoui A. , Dufour G. , Roulet H. , Fromnt M. 
Published: March 2011

AbstractOur Present Understanding of the Mechanisms of the transformation of SiO films under treatments in O2 or Ar plasma at room T, is presented. RBS, IR absorption, XPS, RHEED and TEM techniques have been used to investigate the composition, the chemical and structural nature of the films after oxidizing or non oxidizing treatments. In O2 plasma, SiO is converted into Si02 by room T plasma anodization. The initial step of SiO oxidation, which is believed to be the transformation 2SiO→Si+SiO2, was studied in Ar plasma. We show that the as deposited SiO (not a mixture of Si and SiO2) is subject to disproportionate into the later compounds and that the effects of irradiation by low energy electrons at room T (plasma treatment) are similar to those observed for high T treatments (rapid thermal annealing).
Effects of Si Implantation on Sb Diffusion In Sb-Silica Spin-On Layers
Authors: Moriya N. , Kalish R. , Brener P. , Richter V. 
Published: March 2011

AbstractThe effects of Si implantation (2×1015 · cm-2) on the diffusion of Sb in Sb doped silica (SiO2) spin-on layers and on their hardness were studied. RBS analysis and AES depth profiling showed that the implantation greatly retarded the Sb diffusion (1000–1200°C, 10 sec) in the oxide layer. Hence the high level of Sb near the SiO2/Si interface, which is clearly seen for the unimplanted part of the sample was not noticible in the non implanted part. AES depth profile measurements also showed that the deposited oxide layers were more sputter resistant as a result of the implantation. The above observations are related to the ion induced radiation damage.
Degradation of TiSi2/n+-Polysilicon Interfaces Due to High Temperature Processing
Authors: Shenai K. , Piacente P. A. , Smith G. A. , Lewis N. , Mcconnell M. D. , Norton J. F. , Hall E. L. , Baliga B. J. 
Published: March 2011

ABSTRACTAnalytical results obtained from detailed Secondary Ion Mass Spectrometry (SIMS), Rutherford Backscattering Spectrometry (RBS), Auger analysis, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) of ∼ 2000Å TiSi2/n+ polysilicon interfaces are reported for thermally annealed silicide samples and silicide samples subjected to further high temperature processing. The LPCVD polysilicon was heavily POCI3 doped at 900°C and TiSi was formed by rf sputtering 1000Å Ti and forming the silicide using ?wo successive thermal anneals at 600°C and 800°C in forming gas resulting in a silicide sheet resistance R of 1.45 Ω/□. The high temperature process stability of the silicide – polysilicon interface was investigated by systematically stressing the polycide at process temperatures in the range of 700° C to 1100° C. The silicide was stable for temperatures up to 900° C; however, significant degradation in the silicide sheet resistance, phosphorus, silicon, and titanium redistribution, and agglomeration and film breakage of TiSi2 were observed at higher process temperatures.
Formation of PtSi Using Polycrystalline Si and Different Annealing Sequences
Authors: Chang Chin-An , Segmüller Armin 
Published: March 2011

ABSTRACTFormation of PtSi on As-doped polycrystalline Si is studied using different annealing sequences. An incomplete reaction between the Pt and Si is observed using a one-temperature anneal at 550 ° C, with unreacted Pt remaining in the film which is undesirable for the device processing. Using a three-temperature annealing sequence at 200–300–550 ° C in a N2-H2 mixture, a complete reaction is observed between Pt and Si, with no unreacted Pt detected. The results are similar to that using single crystal Si, except for the less-oriented PtSi formed. The three-temperature annealing process described has thus been shown useful to the fabrication of PtSi contacts at device areas containing either single crystalline or polycrystalline Si.
Piezoresistive Properties of Boron-Doped PECVD Microcrystalline Silicon Films
Authors: Guo Shu Wen , Tan Song Sheng , Wang Wei Yuan 
Published: March 2011

ABSTRACTThe piezoresistive properties of boron-doped PECVD microcrystalline Si films (μc-Si) deposited on SiO2 coated Si, covar or quartz substrates have been investigated. The relations between the gauge factor (G.F.) and doping concentrations as well as the film thickness etc. have been obtained experimentally. The maximum longitudinal G.F. of 25 and 20 are measured for Si and covar substrates respectively. An expression for calculating G.F. of P-type μc-Si is derived theoretically by use of the splitting model of heavy and light hole band at k=0 and the thermionic emission theory. The calculated dependences of G.F. on the doping concentrations, grain size and trap state density agree well with the experimental results, which offer a better understanding of the piezoresistive characteristics of μc-Si or poly-Si, and enable optimized design and fabrication of μc-Si or poly-Si strain gauges.
Polysilicon Super Thin Film Transistor Technology
Authors: Noguchi Takashi , Hayashi Hisao , Ohshima Takefumi 
Published: March 2011

ABSTRACTAdvanced super thin(of less than 800Å) polysilicon films with the grain size of more than lum were developed by applying the Si+implanted amorphization and subsequent annealing. With this film, TFT with superior characteristics could have been fabricated on quartz or SiO2/c-Si substrate. At the process of 600°C, field effect electron mobility as large as 60cm 2/V.s. was obtained. Furthermore, using the high temperature process of 1000°C, electron and hole mobility increased to the value of 120 and 80cm2/V.s, respectively. The values of field effect electron mobility were almost constant over a wide temperature range. The CMOS scanner was fabricated and operated faster than 5MHz. These advanced polysilicon TFT's have a great impact on large size LSI.
Effects of Silicon Implantation and Processing Temperature on Performance of Polycrystalline Silicon Thin-Film Transistors Fabricated from Low Pressure Chemical Vapor Deposited Amorphous Silicon
Authors: Chiang Anne , Huang Tiao Y. , Wu I-Wei , Zarzycki Mark H. , Fuse Mario 
Published: March 2011

ABSTRACTSilicon implantation has been found to dramatically enhance the grain size of polysilicon crystallized from LPCVD a-Si by retarding the nucleation process at the substrate interface. Corresponding improvement in TFT device performance was also observed, resulting in field effect mobilities as high as 109 cm2/Vs in devices with 1000 Å thick Si active layer. This effect is more significant in device fabrication processes with higher temperature, possibly due to increasingly efficient removal of implant related defects.
Leakage and Transconductance in Polysilicon Thin Film Transistors: Effect of Grain Boundary Hydrogenation
Authors: Qian Feng , Kim Dae M. , Kawamoto Galen H. 
Published: March 2011

ABSTRACTThe n- and p-channel field effect transistors are fabricated in as-deposited and grain boundary passivated polysilicon thin films. The performance of these thin film transistors (TFT's) is characterized and compared. Specifically, the transconductance and leakage behavior are discussed in detail in correlation with the grain boundary properties. The I-V characteristics are modeled from a unified point of view.
Poly-Silicon Deposition by Evaporation for TFTs
Authors: Schmolla W. , Diefenbach J. , Blang G. , Senske W. 
Published: March 2011

ABSTRACTPoly-Si films were e-gun evaporated onto glass substrates. The Hall-mobility for holes was found to be about 2 cm2/Vs in undoped poly-Si films deposited at 400°C and 9 cm2/Vs at 500°C. TFTs were fabricated on the base of poly-Si evaporation technique on borosilicate glass at a highest process temperature of 550°C without ion implantation. The electrical TFT characteristics yield electron field-effect mobilities higher than 10 cm2/Vs as well as threshold voltages less than IV and an on/off current ratio in excess of 104.
Crystallization of Amorphous LPCVD Silicon Films and Application to Bipolar and Thin Film Transistors
Authors: Hatalis Miltiadis K. , Greve David W. 
Published: March 2011

ABSTRACTWe studied the crystallization of LPCVD amorphous silicon films by TEM and found that the grain size of crystallized films depends upon the deposition and annealing conditions. The grain size increases as the deposition and/or the annealing temperature decreases. We also investigated the application of crystallized films in the fabrication of polysilicon emitter bipolar transistors and thin film transistors. The performance of bipolar transistors was found to have a small dependence on the grain size. In contrast, the performance of thin film transistors was strongly dependent upon the grain size.
On the Temperature Dependence of Resistivity of Polycrystalline Silicon Films
Authors: Rodder Mark S. , Antoniadis Dimitri A. 
Published: March 2011

ABSTRACTIt is shown that the grain boundary (GB) in polycrystalline-silicon (poly-Si) films need not be modeled as a temperature-dependent potential barrier or as an amorphous region to explain the temperature (T) dependence of resistivity (ρ) in p-type poly-Si films at low T. Specifically, we consider that QB defect states allow for the tunneling component of current to occur by a two-step process. Incorporation of the two-step process in a numerical calculation of ρ vs. T results in excellent agreement with available data from 100 K to 300 K.
Influence of the Decoration by Dislocations on Grain Boundary Passivation by Hydrogen in Silicon
Authors: Ammor L. , Mathian G. , Martinuzzi S. 
Published: March 2011

ABSTRACTIn large grained polycrystalline silicon, the recombination activity of G.B.'s and their passivation by hydrogen is found to be dependent on the decoration by dislocations. Dislocations appear to be preferential paths for in-diffusion, at a depth of a few hundreds of pim's. Similar enhancements of diffusion and passivation exist in grains around dislocations.
Hacroscopic Defects in Epitaxial Silicon on Simox and in Annealed SIMOX
Authors: Mogro-Campero A. , Lewis N. , Al-Marayati S.A. 
Published: March 2011

AbstractEpitaxial silicon layers of 5¼m were grown on SIMOX wafers. The dislocation density decreases by more than an order of magnitude as a function of distance away from the buried oxide. Shallow pits (about 0.5 urn deep and several um wide) are observed on the epitaxial layer with a density of 1-2 mm2. Their density did not change with various processing variations. A search for the origin of the pits by transmission electron microscopy reveals that they may be associated with regions of irregularly thin and sometimes missing buried oxide, which appear after the usual high temperature SIMOX annealing step. These defective regions in the buried oxide appear to initiate twinned growth in the epitaxial silicon, and are associated with pits at the top epitaxial silicon surface.