bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication of the Large-Area Integrated a-Si Solar Cells
Authors: Yamazaki S. , Abe M. , Nagayama S. , Shibata K. , Susukida M. , Fukada T. , Kinka M. , Kobayashi I. , Inushima T. , Suzuki K. 
Published: March 2011

ABSTRACTPIN-structure small-area solar cells using a-Si have been frequently reported on, but only a few reports are available on the study of solar cells using a large-area (10-cm square) substrate, all with a resultant conversion efficiency of above 9.0 %[1,2]. Our study has been concentrated on solar cells using a batch of ten 10-cm square substrates with an average conversion efficiency of 9.5 % or more.As a result, without an anti-reflection coating on the surface of the glass substrate, the following values have been obtained: average conversion efficiency (EFF)=9.63 % (standard deviation of 0.195 %) -Open-circuit voltage (Voc)=12.668 V (standard deviation of 0.215 V) -Short-circuit current (Isc)=78.467 mA (standard deviation of 1.619 mA) -Fill factor (FF)=0.6672 (standard deviation of 0.009)The process, equipment and methods for measurements through which these results were obtained are described below.
Properties of Amorphous Silicon Films Deposited at Rates Higher Than 1 μM/MIN.
Authors: Chu T. L. , Chu Shirley S. , Ang S. T. , Duong A. , Han Y. X. 
Published: March 2011

ABSTRACTThe thermal decomposition of disilane in a helium flow has been used for the deposition of hydrogenated amorphous sil icon (a-Si:H) films on various substrates at rates higher than 1 μm/min, and a-SI:H films with thickness up to 20 μm have been deposited in this manner. Their optical properties, photoconductivity, minority carrier diffusion length, gap state density, etc., have been measured. The electronic properties of these films are superior to those of chemical vapor deposited a-Si:H films heretofore reported, indicating that the thermal decomposition of disilane in a hel ium atmosphere is a promising technique for the deposition of a-SI:H films.
Integrated Series Connection of a-Si:H Solar Cells
Authors: Juergens W. , Kausche H. , Peters W. , Stetter W. 
Published: March 2011

ABSTRACTWe tested several methods of patterning amorphous-silicon (a-Si:H) solar cells to form stripe cells and to connect these stripe cells integrated with cell deposition process to a series-connected module. The patterning techniques used included: laser cut, screen print lift-off techniques, adhesive tapes with lift-off, and a special mechanical milling method. The three layers of a cell which must be patterned are 1. SnO2 :F on glass, 2. a-Si (p(C)in), 3. metal-electrode.We developed a convenient patterning method for a laboratory size with a loss of area of 13 %: 1. laser cut, 2. milling, 3. adhesive tape lift-off. For a higher level of production we tested the following sequence with a loss of area of 4 %: 1. screenprint and lift-off, 2. milling/slotting, 3. screen print and lift-off. The last method has the advantage that without any laser treatment the costs are only third of those of the other methods with a laser cut; so we will eliminate the laser cut in future for manufacturing modules.
Temperature and Light Intensity Dependences of Open Circuit Voltage in a-Si: H Pin Solar Cells
Authors: Jang Jin , Lee Choochon 
Published: March 2011

ABSTRACTThe temperature and incident light intensity dependences of open circuit voltage for hetero-and homojunction a-Si:H pin solar cells have been studied. The temperature coefficient of the open circuit voltage decreases from -2.40 to -2.67 mV/°C as the illumination intensity is decreased from 150 to 7mW/cm2 This is consistent with the empirically calculated open circuit voltages. The diode quality factor obtained under dark condition shows high values(l.6–3.0) and strong temperature dependence. On the other hand, the diode quality factor under illumination is less than 1.5 and shows slight temperature dependence. The results appear to be due to the long dielectric relaxation time compared with the carrier lifetime in the i-layer.
Experimental and Theoretical Results for Light Trapping in High Efficiency a-Si1-xCx:H/a-Si:H Solar Cells Prepared on Granular Tin Oxide.
Authors: Ellis F. B. , Delahoy A. E. , Böhm M. , Cambridge J. A. , Horning T. 
Published: March 2011

ABSTRACTWe examine the morphology and optical properties of fluorine doped tin oxide films prepared by the chemical vapor deposition of tetramethyltin and tin tetrachloride and the influence of these properties on light trapping in amorphous silicon solar cells having the structure glass/SnO2 /P (a-Si1-xCx:H) -i-n/metal. Measured tin oxide properties include total and diffuse transmission as a function of wavelength, angular dependence of the scattered light, surface topography, and sheet resistance. Experimental quantum efficiency plots as a function of wavelength are presented and compared to computer calculations based on multilayer optics programs and measured optical constants. Using granular tin oxide, p-i-n cells 1 cm2 in area have been prepared with efficiencies exceeding 10%.
Properties of Indium Tin Oxide Films Prepared Using Reactive RF Magnetron Sputtering
Authors: Mehra Madhav , Rhodes Howard 
Published: March 2011

ABSTRACTThe results obtained upon reactively RF sputtering indium - tin oxide (ITO) films are presented. It is found that while the amount of oxygen in the chamber is very critical in determining the properties of the films, it is easy to deposit reproducible films even at low oxygen concentrations when using an oxide target. At concentrations of oxygen below 2 vol% the films deposited exhibit almost metallic conductivities, while retaining an average transparency in the visible range of over 85%. The resistivity of these films increases with the oxygen concentration in the chamber, but the transition is not as sharp as that observed upon sputtering a metal target. These films are found to have very good “figures of merit” and are promising in their use as transparent conductors.
A Comparative Study of Hydrogenated Amorphous Silicon Films Prepared by RF Sputtering in He/H2, Ar/H2 and Xe/H2 Mixtures
Authors: Albers Mark L. , Shanks H. R. , Shinar J. 
Published: March 2011

ABSTRACTPreliminary results of a comparative study of some optical and ESR properties of aSi:H films prepared by rf sputtering on a cold substrate in 10 mtorr of either He, Ar, or Xe and 0.5 mtorr H2 are presented. In all cases the concentration of Si-H and Si-H2 bonds, the optical gap and the dangling bond spin density all generally increase as the rf power is decreased from 3.3 to 0.27 W/cm2. However, whereas the optical energy gap of He/H2 sputtered films ranges from 1.26 eV to 2.13 eV, the gap of Ar/H2 and Xe/H2 films sputtered under these conditions only changes from 1.54 to 1.94 and 1.41 to 1.71 eV, respectively. The dangling bond spin densities are lowest (~1017 cm-3) in the Ar/H2 sputtered films at high rf power and highest (~5x1018 cm-3) in Xe/H2 sputtered films at low power.
Proplriies of Post-Hydrogenated Amorphous and Microcrystalline Germanium Films
Authors: Woodyard James R. , Gonzalez-Hernandez J. , Young R. T. , Piontkowski J. 
Published: March 2011

ABSTRACTAmorphous and microcrystalline germanium films prepared by glowdischarge and molecular beam deposition were hydrogenated after deposition, using a 3cm Kaufman ion source. The hydrogen profiles were determined using the N15p nuclear resonance reaction. We found that the surface region hydrogen concentration depended on ion beam modification of the material, and the bulk concentration was determined by the hydrogenation conditions and deposition conditions. The light and dark conductivities wee measured before and after hydrogenation. Several orders of magnitude change in the ratios of the conductivities were measured under optimum hydrogenation conditions. The aclivation energy for electrical conductivity was measured and found to be dependent on film structure thickness and hydrogenation conditions.
Novel a-Si:H Thin Film High Voltage Transistor
Authors: Tuan Hsing C. 
Published: March 2011

ABSTRACTA new novel thin film high voltage transistor in a-Si:H is described in this paper. This new structure extends the operation of a-Si:H TFT to 500 volts or more. The fabrication process of this new high voltage transistor is simple and compatible with that of the conventional low voltage TFT. The high voltage TFT can be switched by low voltage signals and is demonstrated to be capable of switching several hundreds of volts.
Crystallization Rate and Thermal Stability of Te-Based Alloy Thin Films for Erasable Optical Recording
Authors: Ross R. C. , Strand D. A. , Bjornard E. J. , Deneufville J. P. 
Published: March 2011

ABSTRACTErasure speed and thermal stability of a number of Te-based alloys have been measured and compared. A distinct trend of increasing crystallization temperature, Tx, and increasing minimum time required for crystallization, τx, with increasing crosslinking element content is observed. Films which crystallize to form Te are stability limited at Tx≈80°C for τx≈┐μsec. Films which crystallize to form Sb40Te45Se15have Tx160°C at τx≈┐μsec. Static tester recrystallization kinetics and direct observation of cycled tracks by optical and electron microscopy indicate that recrystallization occurs via epitaxial growth from peripheral crystallities and not from internally dispersed nuclei for all materials studied. Thus, crystallization speed is limited by three factors: the intrinsic maximum crystallization velocity of the pure crystal, the diffusion rate of crystal-insoluble crosslinking elements away from the crystallization front, and the geometry of the amorphous and peripheral crystalline zones
Planar and Perpendicular Conductivity of Doping Modulated Amorphous Silicon Multilayers
Authors: Steemers H. , Chen I. , Mort J. , Jansen F. , Morgan M. , Kachonkin N. , Kuhman D. 
Published: March 2011

ABSTRACTThe conductivity of a-Si:H multilayers consisting of alternating boron and phosphorus doped layers has been studied as a function of sub-layer thickness. The planar and perpendicular dark conductivity is compared with theoretical analysis of space-charge doping in these structures and this effect is found to dominate the transport as the sub-layer thickness is reduced below a critical value
Bond Angle Disorder in Tetrahedrally Bonded Amorphous Silicon
Authors: Wong C. K. , Lucovsky G. 
Published: March 2011

ABSTRACTThere have been many studies of the vibrational and optical properties of a- Si and a-Ge that have correlated systematic variations of these properties with films grown and/or annealing temperatures, and have attributed these variations to changes the local atomic structure and intrinsic network disorder that are correlated with the thermal history of a particular sample. The most frequently proposed atomic structure parameter associated with this intrinsic disorder has been the width of the bond angle distribution. We attempted to isolate the effects of bond angle disorder on the vibrational and electronic properties of a-Si using a Bethe Lattice structure that avoids some of the uncertainties introduced by the uncontrolled variation in other atom structure parameters. Using this approach, we show that increases in the width of the bond angle distribution can account for trends in the calculated vibrational and optical properties wth thermal hisrory that are in good qualitative agreement with trends reported in the experiments.
Ab-Initio Theory of Defect Structure in a-Si iH
Authors: Bar-Yam Yaneer , Joannopoulos J. D. 
Published: March 2011

ABSTRACTIt has recently become feasible that theory Will be able to predict the structure of solids “ab-initio”, using only the atomic number of the constituent atoms as input. This is based on recent advances in density-functional theory and pseudopotential theory. A simple physical introduction of the concepts underlying these theories is presented. Special emphasis is given to examining the structure and effective correlation energies of defects in amorphous Si.
Defect Structures Generated by Buried Amorphous Layer Regrowth in <100> Arsenic Implanted Silicon
Authors: Jones Kevin S. , Prussin S. 
Published: March 2011

AbstractPlan-view and 90° cross-sectional TEM examination was used to investigate the correlation between the type of amorphous layer produced and the resulting defect structure observed upon annealing. Both <100> and <111> Si wafers were ion implanted with high energy (190 keV) arsenic over a range of doses(1 × 1015/cm2 to 5 × 1015/cm2). A Wayflow endstation was used allowing ion beam induced epitaxial crystallization (IBIEC)[8] or dynamic annealing of the sample to occur. Implanted <111> Si is shown to form a continuous amorphous layer up to the surface, while <100> implanted Si forms a buried amorphous layer. The regrowth of the buried x-layer by furnace annealing is shown to be responsible for the formation of shear type dislocation loops at the interface where the two x/c regrowth fronts meet (catagory IV defects).[7] However if the buried layer is regrown by dynamic annealing a different structure results.In addition to using <111> wafers, other parameter changes which resulted in the formation of surface amorphous layers included decreasing the implant energy from 190 keV to 100 keV, or implanting the wafer at 77K instead of using the Wayflow endstation. Regrowth of the surface amorphous layers produced by these changes did not result in the formation of shear type dislocation loops. Further annealing of the 100 keV Wayflow implant and the 190 keV 77K implant at 900°C for 30 minutes resulted in the formation of small prismatic extrinsic dislocation loops beneath the location of the original amorphous/crystalline interface (catagory II defects).[71]
Role of Implant Energy on Defect Structures for Phosphorus Implanted Silicon
Authors: Prussin S. , Jones Kevin S. 
Published: March 2011

AbstractA series of 18 wafers were implanted with phosphorus ions covering an energy range of 25 to 180 keV at a dose of 1 × 1015 cm−2 using a Waycool end station which provides good contact between the wafers and a thermal sink. Half the wafers had {100} surfaces and the other half {111} surfaces. The morphology of the as-implanted surface, defined by the thickness of the amorphous layer and whether that layer was submerged or lay at the surface, was affected by implant energy and surface orientation. After a 550°C regrowth and an activation anneal of 30 minutes at 900°C, the defect structures were evaluated by plan and cross-sectional transmission electron microscopy. A dear correlation was found between the implant morphology, the wafer orientation, and the defect structures.
Deep-Levels Associated with Implanted Titanium in Silicon
Authors: Ransom Craig M. , Iyer S.S. 
Published: March 2011

AbstractTitanium was ion implanted at 180 KeV into p-type silicon to form a buried TiSi2 layer. DLTS measurements of n+p junctions have shown two minority carrier traps at Ec − Et = 0.24 and 0.51 eV. Also, a single majority trap at Ev + Et = 0.41 eV was observed. The concentrations of these levels were calculated to be approximately 1013 cm−3. DLTS measurements of low-fluence 50 KeV Ti implantations using Schottky diodes showed four levels dependent on silcon type.
Amorphization of Silicon by Boron Ion Implantation
Authors: Shih Y. , Washburn J. , Gronsky R. , Weber E.R. 
Published: March 2011

AbstractAmorphization of silicon due to implantation of boron ions which is the lightest element used for I.C. fabrication processes, has been systematically studied for various temperatures, voltages and dose rates. A model for formation of amorphous silicon by light ion implantation is proposed. It is suggested that accumulation of point defects and/or clusters is required at the initial stage of amorphization process. Diinterstitial -divacancy pairs are suggested to be the embryos of amorphous zones formed during implantation at room temperature. Out -diffusion of highly mobile interstitials during amorphization is thought to explain differences in the critical energy for amorphization with low and high energy implantation at liquid nitrogen temperature.
Application of The Silicon Interstitial Based Intrinsic Gettering Process to the Formation of Multilevel Defect Structures
Authors: Nauka K. 
Published: March 2011

AbstractThe new intrinsic gettering mechanism based on the interactions of silicon interstitialshas been studied in float zone silicon with virtually zero oxygen content. Silicon wafers were subjected to the high-low-medium temperature annealing cycle, with the high temperature step carried out subsequently in an inert ambient, followed by the dry 02, followed by an inert ambient. The annealing caused formation of a multilevel structure consisting of two defect free regions with a high lifetime value, separated by a layer with high defect density and a low lifetime value. The experimental data corresponds to the theoretical calculations describing silicon interstitial injection during dry 02 oxidation and their diffusion during annealing in an inert ambient.
Interfacial Tunnel Structures In Cmos Source/Drain Regions Following Selective Deposition of Tungsten
Authors: Deblasi J.M. , Sadana D.K. , Norcott M.H. 
Published: March 2011

AbstractThe influence of B and As ion implantation on the location and density of interfacial tunnels, the extent of lateral encroachment, the amount of silicon consumed, and the crystallographic defects in CMOS source/drain structures following selective chemical vapor deposition of tungsten has been characterized.
Correlation Between Ti-Silicided Shallow Junction Diode Leakage and Titaniun Diffusion during TISI2 Fornation
Authors: Nauka K. , Amano Jun , Scott M.P. , Weber E.R. , Turner J.E. , Tsai R. 
Published: March 2011

AbstractDeep level transient spectroscopy (DLTS) in conjunction with other analytical techniques was used to establish a correlation between the leakage current in the TiSi2/p+/n-Si shallow diodes (0.25 micron) and the Ti-related Ec - 0.23 eV deep trap. It was found that Ti diffused into the junction region durin the TiSi2 formation and caused leakage currents with values up to 2 × 10−8 A/cm2. Further increases of the leakage current were related to the formation of a TiSi2/n-Si Schottky barrier.
Effectiveness of CVD thin Film Backside Gettering and Its Interaction with Intrinsic Gettering
Authors: Wong C.-C. D. , Hahn S. , Ponce F. A. , Rek Z. U. 
Published: March 2011

AbstractThe effectiveness of CVD thin film backside gettering on n-type CZ silicon wafers for CMOS technology has been investigated using optical techniques for bulk microdefect analyses and transmission electron microscopy for interfacial structure study. The deposition of LPCVD polysilicon (500-2000 nm), silicon nitride (150 nm), or poly/nitride films on the backside of Si wafers was found to enhance the bulk precipitation. Bulk microdefect density increased as the thickness of polysilicon increased. At the polysilicon/silicon interface, no extended line defects from polysilicon were observed. Based on the results of minority carrier lifetime and oxide breakdown measurements, the best gettering efficiency was given by 1300 nm polysilicon backside gettering scheme.
Microstructure and Resistivity OFCr75 Si25 Thin Films
Authors: Weiss B. Z. , Tu K. N. , Smith D. A. 
Published: March 2011

AbstractThe electrical and microstructural changes of initially amorphous Cr75Si25 thin coevaporated alloy films have been studied as a function of temperature from room temperature to 950°C. Crystallization occurs in two stages. In the “primary” stage the major portion of the amorphous film crystallizes and a steep drop in resistivity occurs. In the “secondary” stage the amorphous residue crystallizes and is accompanied by a further gradual decrease in resistivity. The resistivity depends linearly on the volume fraction Vτ(t) crystallized to give Cr3Si only for Vτ(t) < 0.35.
Furnace Annealed Thin Films of Plasma Enhanced Chemical Vapor Deposited Titanium Borides on Silicon
Authors: Williams L. M. 
Published: March 2011

AbstractThin films of titanium borides, deposited onto silicon substrates at 600 °C using plasma enhanced chemical vapor deposition, were annealed in a furnace at temperatures from 700 °(C to 990 °C. Structural properties and electronic properties were measured for the annealed films and the asdeposited films for comparison. Sheet resistances for the films show about a 35% decrease after anneals at 990 °(C. The reduction in sheet resistance appears to be relatively insensitive to the length of the anneal time. X-ray diffraction spectra of the as-deposited films show no peaks that are attributable to crystalline titanium borides; however, there are diffraction peaks that are believed to be caused by products from reactions between the titanium borides and the silicon substrate during deposition. There is evidence that crystalline titanium diboride may start to form during the anneal at 990 °C.
Electrical Characterization of ZrN
Authors: Krusin-Elbaum L. , Brodsky S. , Ahn K. 
Published: March 2011

AbstractWe have investigated reactively sputter',d ZrN, the most thermally stable of the refractory metal nitrides, for its applicability as a submicron gate electrode. One would require for such gate electrode in addition to the lowest possible resistivity, a metal work function that will tailor the threshold voltage of metal/oxide/semiconductor (MOS) field effect transistor in such a way as to minimize the channel implant. Having these requirements in mind, we have measured the temperature dependence of resistivity, its dependence on the annealing temperature and work function of ZrN films. Our best films have resistivity, p of 20 A2-cm, comparable to TiSi. We find that p of as-deposited films being nearly stoichiometric, decreases about 20% after 1000°C anneal. Such anneal does not significantly alter the average grain size, which remains about 300 A even at this temperature. The temperature dependence of p at low temperatures indicates phonon scattering mechanism and we suggest that small amounts of oxygen are re- sponsible for residual resistance. The films undergo superconducting transition at 7.5-8 K and this transition provides an additional check on the compositonal homogeneity of the films. The work function, determined from the capacitance-voltage (C-V) characteristics of ZrN capacitors with various thicknesses of Si02, has value 0. = 4.6 Volts, at the midgap between n+ and p+ polysilicon and thus is applicable to 0.5 1m N-MOS and submicron C-MOS.
An Analysis of Conventional and Self-Aligned four Terminal Resistor Structures for The Determination of The Contact Resistivity from End Resistance Measurements
Authors: Suni I. , Finetti M. , Grahn K. 
Published: March 2011

AbstractA computer model based on the finite element method has been applied to evaluate the effect of the parasitic area between contact and diffusion edges on end resistance measurements in four terminal Kelvin resistor structures. The model is then applied to Al/Ti/n+ Si contacts and a value of contact resistivity of Qc = 1.8×10−7.Ωcm2 is derived. For comparison, the use of a self-aligned structure to avoid parasitic effects is presented and the first experimental results obtained on Al/Ti/n+Si and Al/CoSi2/n+Si contacts are shown and discussed.