bluuebunny/crossref_metadata_2025_split huggingface dataset:
Point Defect Engineering Applied to Shallow Junction ULSI Processing
Authors: Rozgonyi George A. , Honeycutt J. W. 
Published: March 2011

AbstractWe describe how a simple qualitative understanding of the interfacial reactions occurring during typical ULSI processes for junction formation, dopant activation, and contact silicidation can be used to eliminate end-of-range interstitial dislocation loops and beneficially impact the diffusion of dopants. Following a brief discussion of the well-documented effects of oxidation and nitridation on extended defects and dopant diffusion, conditions for elimination of implantation-induced defects are specified. Cross-section and plan-view TEM along with angle lapping and chemical etching of implanted and diffused junctions are presented to illustrate the application of point defect engineering to process technology.
New Features of Dark and Photoconductivity Response of Low Energy Ar+ Ion bombarded GaAs
Authors: Vaseashta A. , Burton L. C. 
Published: March 2011

AbstractPhotoconductivity measurements have been made on three SI GaAs sample types: Ar+ ion etched at leV, 3keV, and unetched. Measurements were made versus time, wavelength, and temperature. Photoquenching was done at 1.19 and 2.0eV energy.Some distinct changes in photoconductive properties are caused by the ion etch: 1) Increase in dark resistance; 2) presence of persistent photoconductivity; 3) increased photosensitivity; 4) increase In quenching rate under 2eV illumination; 5) destruction of the 0.47eV thermally activated photoconductivity.All samples exhibit Shockley-Read recombination controlled photoconductivity below a temperature of 125K, with the same apparent trap location, at 0.26eV above EF.
Si Ion Implantation in InAlAs/InGaAs Heterostructures
Authors: Descouts B. , Duhamel N. , Rao E. V. K. , Gao Y. , Praseuth J. P. 
Published: March 2011

AbstractSi29 implants have been performed in InGaAs and InAlAs single layers as well as in InGaAs/InAlAs heterostructures. Nearly 100% activation has been obtained in InGaAs after conventional furnace annealing or rapid thermal annealing. On the other hand, a low activation efficiency (30%) has been observed in InAlAs. A preliminary photoluminescence measurements study shows that an appreciable fraction of Si exists in the form of complex centers. Hall effect and specific contact resistivity maps carried out in the heterostructures indicate a very good homogeneity of the electrical parameters over a 4 cm2 sample and give a satisfactory value of the specific contact resistivity (10−7 ω.cm2)
Studies on Phosphorus-Implantation and the Annealing of Cadmium Telluride and Copper Indium Disulfide
Authors: Hsu Y. J. , Hwang H. L. , Ueng H. Y. 
Published: March 2011

AbstractThe doping efficiencies obtained in phosphorus-implanted cadmium telluride and copper indium disulfide annealed by pulse electron beam were higher than those annealed by conventional thermal method. To get insights into this phenomenon, electron paramagnetic resonance measurements were performed for both crystals at various stages during the doping process. The results indicated that the pulse electron beam annealing could effectively eliminate the phosphorus interstitials in the implanted crystals but the thermal annealing could not. This shows the significant effect of melting crystals by pulse electron beam annealing to obtain high doping efficiencies.
ION Induced Crystallization and Amorphization of Silicon
Authors: Jackson Kenneth A. 
Published: March 2011

AbstractExtensive experimental investigations which have been reported on the ion-induced motion of the interface between the crystalline and amorphous phases of silicon are shown to fit a model based on a single defect. The model accounts for the temperature and flux dependence of the interface motion. The defects annihilate each other by binary recombination, and have a motion energy of 1.2 eV. The defect is believed to be the dangling bond in the amorphous phase.
Plasma Immersion Ion Implantation for Impurity Gettering in Silicon
Authors: Wong H. , Qian X. Y. , Carl D. , Cheung N. W. , Lieberman M. A. , Brown I. G. , Yu K. M. 
Published: March 2011

AbstractWe have utilized plasma immersion ion implantation (PIII) to demonstrate effective gettering of metallic impurities in silicon wafers. Metallic impurities such as Ni, Cu or Au were intentionally diffused into Si as marker impurities. The Ar or Ne atoms were ionized in an electron cyclotron resonance (ECR) plasma chamber. The ions were accelerated by a negative voltage applied to the wafer and implanted into the wafer. The as-implanted saturation dose can be as high as 5×1016cm−2. After an annealing step at 1000°C for 1 hour in a N2 ambient, the retained doses and the amount of gettered impurities were measured with Rutherford backscattering spectrometry (RBS). With a retained Ar dose in 1015cm−2 range after annealing, the gettered Ni, Cu and Au were 3.0×1014cm−2, 3.0×1014cm−2 and 4.4×1013cm−2 respectively.
Effect of Si and Ge Interface Layers on the Schottky Barrier Height of Metal Contacts to GaAs
Authors: Waldrop J.R. , Grant R.W. 
Published: March 2011

ABSTRACTA new approach for extending the range of the Schottky barrier height ϕB of metal contacts to (100) GaAs is described. Very thin (∼ 10-30Å) heavily n-type and p-type Si or Ge interlayers are found to directly alter the GaAi interface Fermi energy EF. X-ray photoemission spectroscopy is used to determine EF during contact formation and the corresponding ϕB for thick contacts is measured by electrical methods. In an appropriate structure the ϕB range for contacts to n-type GaAs is ∼ 0.25 to 1.0 eV. For p-type GaAs ϕB has been increased to as much as 0.9 eV. This method of ϕBcontrol can be used for both Schottky barrier contact and nonalloyed ohmic contact applications. The results are interpreted in terms of a simple heterojunction model.
Defect Reactions at Metal-Semiconductor and Semiconductor-Semiconductor Interfaces
Authors: Walukiewicz W. 
Published: March 2011

ABSTRACTA recently proposed, new approach to the problem of native defect formation in compound semiconductors is presented. The approach is based on the concept of amphoteric native defects. It is shown that the defect formation energy as well as structure and properties of simple native defects depend on the location of the Fermi level with respect to an internal energy reference: the Fermi level stabilization energy. The known location of the stabilization energy determines the electronic part of the defect formation energy and allows for a quantitative description of a variety of phenomena including: the formation of defects at metal-semiconductor interfaces, doping induced superlattice intermixing and limitations of free carrier concentrations in semiconductors.
Ohmic Contact Formation Mechanism in the Ge/Pd/N-GaAs System
Authors: Marshall E.D. , Lau S.S. , Palmstrøm C.J. , Sands T. , Schwartz C.L. , Schwarz S.A. , Harbison J.P. , Florez L.T. 
Published: March 2011

ABSTRACTAnnealed Ge/Pd/n-GaAs samples utilizing substrates with superlattice marker layers have been analyzed using high resolution backside secondary ion mass spectrometry and cross-sectional transmission electron microscopy. Interfacial compositional and microstructural changes have been correlated with changes in contact resistivity. The onset of good ohmic behavior is correlated with the decomposition of an intermediate epitaxial Pd4(GaAs,Ge2) phase and solid-phase regrowth of Ge-incorporated GaAs followed by growth of a thin Ge epitaxial layer.
Equilibrium Phase Diagrams for Analysis of the Oxidation of III-V Compound Semiconductors
Authors: Schwartz G. P. 
Published: March 2011

ABSTRACTThe phases which result from the oxidation of III-V compound semiconductors can be predicted from a knowledge of the condensed phase portion of their equilibrium phase diagrams. Examples will be shown for arsenides, antimonides, and phosphides. Use of these diagrams explicitly presumes equilibrium growth conditions, and that assumption often fails. In such cases kinetic rather than thermodynamic factors dominate the determination of the observed phases. Examples of this phenomenon for anodic oxidation will be presented. Recent interest in high pressure oxidation conditions as a means of alleviating kinetic limitations will be discussed for InP. The phase diagrams can also be used to predict interfacial reactions under certain conditions and data for GaAs will serve to illustrate this point.
Mbe Growth pf Ca5Sr5F2 on (100), (111), (511), and (711) GaAs Surfaces
Authors: Young K. , Horng S. , Kahn A. , Phillips Julia M. 
Published: March 2011

ABSTRACTWe have used molecular beam epitaxy to grow CaxSr1−xF2 films of various thicknesses on GaAs substrates with different orientations, i.e. (100), (111)A, (511)A, (511)B, (711)A and (711)B. On all orientations, the same crystallographic direction is normal to the surface in both the substrate and fluoride film. For all orientations except (111), the fluoride surface is reconstructed with (111) facets. Without annealing, the best crystallinity is obtained for the (100), (111) and (511)B orientations.
The “Buffer” Layer in the Cvd Growth of β-SiC on (001) Silicon
Authors: Cheng T. T. , Pirouz P. , Powell J. A. 
Published: March 2011

ABSTRACTThe concept of a “buffer” layer in the epitaxial growth of compound semiconductors on (001) silicon substrate is discussed on the basis of homogeneous and heterogeneous surface nucleation. Experimental results on the nucleation of β-SiC on (001) Si by Chemical Vapor Deposition (CVD) are presented and they are discussed in terms of the model for the growth of the buffer layer.
Characterization of Gaas/Si/GaAs Heterointerfaces
Authors: Liliental-Weber Zuzanna , Mariella Raymond P. 
Published: March 2011

ABSTRACTTransmission electron microscopy of GaAs grown on Si for metal-semiconductor-metal photodetectors is presented in this paper. Two kinds of samples are compared: GaAs grown on a 15 Å Si epilayer grown on GaAs, and GaAs grown at low temperature (300°C) on Si substrates. It is shown that the GaAs epitaxial layer grown on thin Si layer has reverse polarity to the substrate (antiphase relation). Higher defect density is observed for GaAs grown on Si substrate. This higher defect density correlates with an increased device speed, but with reduced sensitivity.
Coherency Strain of an Overgrown Island
Authors: Lee J. K. , Hackney S. A. 
Published: March 2011

ABSTRACTThe lattice misfit strain in an overgrown island is considered to be accommodated by twodistinctive domains; a pure coherency domain (ε domain) and a domain of misfit dislocations (δ domain). By introducing such two different constituents, the model predicts the transition condition from a “single phase” state (ε phase) to a “two-phase mixture” (ε+δ) as a function of misfit strain. Further, as in the chemical thermodynamics of a binary alloy system, energy vs. misfit strain diagrams allow us to understand possible existence of various metastable states which may be associated with an overgrowth.
Rheed Observation of Lattice Relaxation During Ge/Si(O01) Heteroepitaxy
Authors: Miki Kazushi , Sakamoto Kunihiro , Sakamoto Tsunenori 
Published: March 2011

ABSTRACTWe report the dynamic RHEED (reflection high energy electron diffraction) observation during Ge/Si(001) heteroepitaxy at various growth temperatures. The RHEED intensityanalysis and the in-plane lattice constant analysis reveal a growth fashion and lattice relaxation. Both of them depend strongly on growth temperature.
Defects and Strain in GexSi1−x Layers Grown by Rapid Thermal Processing Chemical Vapor Deposition
Authors: Jung K. H. , Kim Y. M. , Chun H. G. , Kwong D. L. , Rabenberg L. 
Published: March 2011

ABSTRACTWe have grown single and multi-layer epitaxial GexSi1−x/Si structures by RTPCVD on (100)Si substrates using GeH4 and SiH2Cl2 at 900°C and 1000°C with SiH2Cl2:GeHH4 ratios of 14:1 to 95:1 at 5 Torr. Plane view TEM micrographs indicate misfit dislocation free layers were grown for Ge concentrations of up to 13%. Misfit dislocation networks aligned along <110> were formed at the interface of films with higher Ge concentrations. Plane view TEM micrographs also showed dislocation loops at the interface. When the SiH2C12:GeH4 ratio used was less than 25:1, the GexSil−x layer grew by three-dimensional nucleation, resulting in a high density of defects.
Creation of Interface States at the Silicon/Silicon Dioxide Interface by UV Light Without Hole Trapping
Authors: Schubert W. K. , Seager C. H. , Brower K. L. 
Published: March 2011

ABSTRACTPhotoinjection of electrons into silicon dioxide in metal-oxide-semiconductor (MOS) capacitors with 3.5 eV light is shown to create interface states with no apparent hole trapping precursor. The creation rate of these interface states depends strongly upon whether injection is from the gate metal or the silicon substrate, and on the forming gas annealing sequence used to passivate growth-induced interface states. A mechanism involving electron-induced release of hydrogen in the oxide is consistent with some aspects of the data.
Molecular Beam Epitaxy on the (NH4)2Sx-Treated Surface of GaAs
Authors: Oigawa H. , Kawabe M. , Fan J.-F. , Nannichi Y. 
Published: March 2011

ABSTRACTWe have found that treatment with a solution of ammonium sulfide containing excess sulfur [(NH4) 2Sx] produced a stabilized surface of GaAs. The treated surface is covered with a monomolecular layer of sulfur, and oxygen atoms are prohibited from adsorbing chemically on this surface. We checked the durability of the treated surface to heat treatment to find that it was stable up to more than 500 °C. Epitaxial growth of an Al film was demonstrated on the (NH4) 2Sx-treated surface. The presence of sulfur atoms at the interface by this treatment was found to suppress the chemical reaction between the metal and GaAs. Low temperature GaAs epitaxy was demonstrated on the sulfide treated surface without conventional heat treatment. The surface treatment correlates with changes in Schottky barrier height with various metals, which suggests that the surface states of GaAs are decreased remarkably.
Preparation of Si Thin Films by Spontaneous Chemical Deposition
Authors: Hanna Jun-Ichi , Kamo Akira , Komiya Tohru , Nguyen Hien D. , Shimizu Isamu , Kokado Hiroshi 
Published: March 2011

ABSTRACTA novel method for preparing photoconductive Si thin films termed “Spontaneous Chemical Deposition”, is proposed, in which silane is decomposed spontaneously by gas phase reactions with fluorine at reduced pressure. With the external parameters in the gas phase reaction such as a gas flow ratio of SiH4 to F2 and the reaction pressure and temperature, the Si-network structure of the films can be controlled intentionally, resulting in a reduction of the hydrogen content, CH and a variety of the films from “amorphous” to “microcrystalline”.
Equilibration Kinetics in Interstitially Doped a-Si:H
Authors: Winer K. , Street R. A. 
Published: March 2011

ABSTRACTThe time dependence of the dc conductivity of Li- and Be-doped a-Si:H after thermal quenching is reported. The equilibration kinetics, similar to that observed in substitutionally-doped a-Si:H, is characterized by stretched exponential decays and activated time constants. The equilibration times for Bedoped a-Si:H were too short (< 1 min) for the kinetics of equilibration to be accurately measured. In Li-doped a-Si:H, the equilibration time constants were longer than those in 1% P-doped a-Si:H, which is due to the smaller carrier concentrations in the Li-doped a-Si:H films.
Growth of Crystalline Silicon, Microcrystalline and Epitaxial at Low Substrate Temperature
Authors: Tanabe H. , Azuma M. , Uematsu T. , Shirai H. , Hanna J. , Shimizu I 
Published: March 2011

ABSTRACTBoth microcrystalline and epitaxially grown Si thin films were prepared at low substrate temperature from different precursors under control of atomic hydrogen. With the precursors, SiHn (n≤3), generated by plasma-induced decomposition of Sil4, microcrystalline Si was formed through the island-like clusters with the aid of atomic hydrogen, while two-dimensional growth was caused with the precursors, SiHnFm (n+m≤3) generated from SiF4.
Steady-State Photoconductivity in Undoped Amorphous Silicon
Authors: Liu Jeffrey Zhaohuai , Wagner S. 
Published: March 2011

ABSTRACTAn analytical expression for the thermal activation energy of the steady-state photoconductivity is shown to agree with experimental data in a range of temperature and generation rate for undoped hydrogenated amorphous silicon (a-Si:H). This agreement supports our suggestion that the commonly observed small activation energy of the photoconductivity in undoped a-Si:H originates in the strong temperature dependence of the quasi-Fermi level for electrons.
Development of Spice Models for Amorphous Silicon Thin-Film Transistors
Authors: Hack M. , Shaw J. G. , Shur M. 
Published: March 2011

ABSTRACTIn this paper we describe a new analytic model for both the current-voltage and capacitance-voltage characteristics of amorphous-silicon thin-film transistors. This analytic model has been incorporated into a circuit simulation program (SPICE) to provide an accurate comprehensive three terminal model for amorphous-silicon thin-film transistors. We present results showing good agreement between circuit simulations based on this new device model and experimental data. The development of amorphous silicon SPICE simulation tools increases the design accuracy of advanced analog and digital circuits.
Theory of Vertical Amorphous Silicon Thin-Film Transistors
Authors: Shaw J. G. , Hack M. 
Published: March 2011

ABSTRACTWe describe a vertical amorphous silicon thin-film transistor which is easy to fabricate and has a very short channel length that is determined by deposition, not lithography. Our vertical TFTs are compatible with large-area processing techniques andd have suitable terminal characteristics for use in practical circuits. Unlike a conventional thin-film transistor, the current path is primarily parallel to the electric field created by an insulated gate electrode. A two-dimensional computer program is used to analyze these devices and guide their design and optimization. We show how to suppress excessive leakage currents and improve the saturation of the output characteristics by a novel current-blocking technique.
Degradation of High and Low Voltage Amorphous Silicon Thin Film Transistors Due to Air Leak
Authors: Martin Russel A. , Tsai C. C. 
Published: March 2011

ABSTRACTAmorphous Silicon TFT performance is shown to be strongly affected by an air leak into a plasma deposition system during film growth. The introduction of a controlled air leak into the system raises the oxygen content of the active layer. For both high and low voltage transistors (HVTFT & LVTFT) the drive current, FET mobility, and threshold voltage are degraded with increasing leak rate. Moreover, the stability of HVTFTs containing a space charge limited region is adversely affected by increasing leak rate.
Geometry Dependence of the Transport Parameters in Field Effect Transistors Made from Amorphous Silicon
Authors: Griep S. 
Published: March 2011

ABSTRACTField effect transistors (TFTs) with different channel lengths L and widths W have been prepared to study the influence of the geometry on the characteristics of the transistors. The mobility μ and the threshold voltage Vth are determined from the √Ids (Uds) plot. Effective values of L and W can be determined by analyzing their dependence on geometry. It can be shown that parts of the amorphous silicon which are outside the area between the source and drain contacts contribute to the current. The reason for this is that the drain-source field spreads out into these regions. Taking this effect into account we obtain the values for the mobility μ. The part of the overlap contributing to the transistor current is smaller than 2 μm.
The Internal Photoemission of Electrons and Holes from Metals into Hydrogenated Amorphous Silicon
Authors: Hicks M. , Lee S. , Kumar Satyendra , Wronski C. R. , Pinarbasi M. 
Published: March 2011

ABSTRACTInternal photoemission is used to investigate the mobility edges in high quality, undoped, hydrogenated amorphous silicon (a-Si:H). The detailed studies carried out on intimate metal/ a- Si:H Schottky barriers are described and results on the electron barrier heights of these contacts formed on a-Si:H having different bandgaps are presented. The observed dependence of the barrier heights on changes in the optical gap due to hydrogen incorporation indicates that not all of these changes are due to the shifts of the valence band edges. The first results on the injection of holes into the valence band of a-Si:H are reported.
Detailed Study of Ion Bombardment in Rf Glow Discharge Deposition Systems: The Role of Helium Dilution
Authors: Cabarrocas P. Roca I 
Published: March 2011

ABSTRACTWe present a detailed study of the variables (reactor geometry, gas pressure, rf power and silane dilution) which control the flux and energy of the ions impinging on the substrate in capacitively-coupled rf glow discharge systems. The ion flux and ion energy, measured with an electrostatic energy analyzer, were found to be largely dependent on the reactor geometry, which was quantified by the ratio of the area of the grounded surfaces Sg to the area of the rf electrode Sc. Special attention was paid to the effects of the dilution of silane in hydrogen, helium and argon. Helium and hydrogen dilution were found the most effective means to increase ion bombardment while argon dilution has little effect on the ion energy distribution. Furthermore, it is likely that ion bombardment at moderate energy (Eion < 70 eV) does not induce any serious degradation of the electronic properties of a-Si:H films.
Correlation Between Microstructure and Optoelectronic Properties of a-SiGe:H
Authors: Weller H. C. , Bauer G. H. 
Published: March 2011

ABSTRACTA dense network structure with low defect and void densities in a-SiGe:H alloys are realized by remote deposition conditions (triode reactor configuration, H2-dilution of SiH4+GeH4 gas mixture). The material properties are characterized by optical transmission, photothermal deflection spectroscopy (PDS), scanning electron microscopy (SEM), and space charge limited currents (SCLC). A high refractive index n∞. (λ->∞) and a fine surface structure in SEM images indicate an optical dense network, moreover the defect density determined by SCLC is reduced in comparison to films deposited in a conventional diode reactor. The substrate temperature TS, one of the key parameters for high quality low gap material, sensitively influences the optical and electronic properties of the samples. The optimum substrate temperature (TS≍=225°C) is found to be lower than for the deposition of a-Si:H (TS≍250°C).
Potential Profiles in Amorphous Alloys Devices
Authors: Vanderhaghen R. , Longeaud C. 
Published: March 2011

ABSTRACTThe standard time of flight technique is modified to analyse the internal field profiles in hydrogenated amorphous silicon or amorphous alloys devices. The spatial resolution of the field can be better than a thousand angstroms.With this method the internal field profile in a Schottky structure, built in the sandwich geometry Pt/a-SiGe:H/Cr, was studied. The field profile is found to decrease exponentially with the distance to the Pt/a-SiGe. We also underline the non-ohmic behaviour of the a-SiGe/Cr interface. The shape of the internal field along the intrinsic zone in P-I-N devices is also studied by the same method.The variations of the field profiles in both devices (Schottky and P-IN) with various applied DC biases is presented.