bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real Time Monitoring Of The Optical Properties Of Cw Laser Annealed Silicon
Authors: Ready John F. , Thompson Mcclure B. , Brewer Terry L. , Larson William L. 
Published: March 2011

ABSTRACTThe surface reflectivity of ion implanted silicon is a function of the entire past history of the material, including the nature of the implanted species and the implant dose. It is influenced by interference effects, arising from discontinuities in index of refraction at the surface and at the boundary between damaged and undamaged material. The reflectivity may be either higher or lower than that of the unimplanted silicon. As the crystalline silicon regrows from below, the reflectivity changes because of variable constructive or destructive interference. This paper describes monitoring of the surface reflectivity during continuous laser annealing. The beam from a continuous argon ion laser is scanned in a raster pattern over the silicon surface. The surface reflectivity for a HeNe laser beam is monitored as a function of time during crystalline regrowth. The reflectivity contains an oscillatory component which arises because of changes in interference due to the decreasing thickness of the noncrystalline layer. The oscillatory behavior produces a signature characteristic of the annealing. The reflectivity monitoring technique is useful for investigating the influence of parameters such as the spatial profile of the laser beam and the implantation dose on the annealing characteristics. The results are correlated with measurements of the depth profile of the implanted ions, as revealed by anodic oxidation and stripping.
Infrared Optical Properties of Ion Implanted and Laser Annealed Silicon
Authors: Miyao Masanobu , Motooka Teruaki , Natsuaki Nobuyoshi , Tokuyama Takashi 
Published: March 2011

ABSTRACTElectronic states of extremely heavily doped n-type Si obtained by high dose ion implantation and laser annealing are investigated by measuring the infrared optical properties. Free carrier effective mass (m*) and carrier relaxation time (τ) are obtained as a function of carrier concentration (1019−5×1021 cm−3). Values of m* and τ increase and decrease, respectively, with the increase of carrier concentration. These results are discussed in relation to the occupation of electrons in a new valley of the conduction band.
Pulsed Laser Annealing Effects in High Dose Rate Silicon Implants
Authors: Williams J.S. , Pogany A. P. , Beanland D. G. , Chivers D. J. , Kenny M. J. , Rose A. , Scott M. D. 
Published: March 2011

ABSTRACTHigh resolution Rutherford backscattering and channelling TEM and electrical measurements have been employed to investigate pulsed-ruby laser annealing effects in high dose rate ion implanted silicon wafers. The laterally non-uniform, part amorphous, part crystalline disordered structure which can result from high dose rate implants has been utilized to investigate the selective removal of amorphous or crystalline damage at near-threshold laser powers. Evidence is found for preferrential recrystallisation of amorphous damage regions over a broad laser power window which is below the threshold power required to melt adjacent crystalline silicon. At laser power levels above the crystalline-to-melt threshold, excellent uniformity in damage removal and electrical properties were obtained over the entire wafer.
Multiple-Scan E-Beam Method Applied to a Range of Semiconducting Materials
Authors: Shah N.J. , Mcmahon R.A. , Williams J.G.S. , Ahmed H. 
Published: March 2011

ABSTRACTThis paper describes the conditions for activating ion implants in a range of semiconductor materials in the solid state. This includes phosphorus and arsenic implants into silicon, boron and phosphorus implants into SOS, gallium into germanium and silicon into gallium arsenide. For each material the restoration of electrical activity correlates with structural data from RBS analysis. Negligible implant diffusion occurs for the typical annealing treatments which result in full activation of dopants.
Transient and Furnace Annealing of Ion Implanted Gallium Arsenide
Authors: Williams J. S. , Harrison H. B. 
Published: March 2011

ABSTRACTThis review examines the annealing behaviour of ion implanted gallium arsenide during furance, laser and e-beam processing.The two annealing regimes, namely solid phase regrowth via furnace or CW laser/e-beam annealing and liquid phase epitaxy produced by pulsed lasers/e-beam, are examined in some detail.Emphasis is placed upon an understanding of the physical processes which are important during the various annealing modes.Comparison with the annealing behaviour of ion implantedelemental semiconductors(notably silicon) is made throughout the review to highlight relevant similarities and differences between compound and elemental semiconductors.The electrical properties of annealed gallium arsenide layers are not treatedin any detail, although particular observations which are relevant to the annealing processes are briefly discussed.
Pulsed Ruby Laser Annealing of Zn, Mg, Se and Si Ion Implants in Semiconducting Gaas
Authors: Lowndes Douglas H. , Cleland J. W. , Christie W. H. , Eby R. E. 
Published: March 2011

ABSTRACTThe properties of p+ and n+ layers formed by pulsed ruby laser annealing (PRLA) of shallow (Rp ~ 320–680 Å) implantations of Mg, Zn, Si and Se ions in both n- and p-type semiconducting GaAs have been evaluated using a combination of SIMS and electrical properties measurements. High activation (> 80%) was obtained for high dose (5 × 1015 ions/cm2 ) implants of both Mg and Zn, within a pulsed laser energy density “window” 0.5 ≤ Eλ ≤ 0.8 J/cm2 (FWHM pulse duration = 20–25 ns). SIMS measurements following PRLA show a wellbehaved increasing penetration of dopant ions into the GaAs substrate, with dopant ion concentrations well in excess of 1020 ions/cm3 in the near-surface region. Measured hole mobilities are consistent with the values anticipated for these high concentrations of ionized impurity scattering centers.
Computer Model of the Temperature and Carrier Concentration Induced in Si by Nanosecond and Picosecond Laser Pulses
Authors: Lietoila Arto , Gibbons James 
Published: March 2011

ABSTRACTA set of simultaneous equations for lattice temperature, carrier concentration and carrier temperature in Si is numerically solved for typical nanosecond and picosecond laser pulses. The calculated threshold energies required to reach Si melting temperature are consistent with measured thresholds to reach a flat-top reflectivity of ~ 70% for typical nanosecond pulses at 1.06 and .53 µm. In the picosecond regime, almost the entire pulse energy is at first stored in the carrier system, and a carrier temperature exceeding 30,000 K is achieved for a 3 J/cm2, 30 ps pulse at 1.06 µm. In this case, the surface carrier concentration reaches a high enough value to cause an enhanced reflectivity from the plasma lasting for at least 0.1 ns. The lattice temperature reaches 1410°C, while carriers relax their energy to the lattice after the pulse, and the energy stored in the carrier system would be enough to supply the heat of fusion at the silicon surface.
Behavior of Metastable Te Donor Concentrations in Q-Switched Ruby Laser Annealed GaAs
Authors: Pianetta P. , Amano J. , Woolhouse G. , Stolte C. A. 
Published: March 2011

ABSTRACTThe thermal behavior of Te implanted, laser annealed GaAs was investigated by helium backscattering spectroscopy and transmission electron microscopy in order to correlate structural changes with the two stage reduction in the carrier concentration due to post laser anneal heating above 200°C. The activation energy for stage one which occurs in the range 200–400°C was determined to be approximately 1.3 eV. Post laser anneal heating at 450°C caused no observable structural changes. On the other hand, 850°C post laser anneal heating induced the formation of precipitates and dislocation loops as well as narrowing the channeling half-angle of Te by about 11%.
Pulse Diffused N+ Layers in GaAs
Authors: Eirug Davies D. , Ryan T.G. , Lorenzo J.P. , Kennedy E. F. 
Published: March 2011

ABSTRACTPulse diffusion has been used for doping GaAs n-type to over 1019 cm−3. Surface arsenic loss is avoided through using As2Se3 as the diffusion source. A reduction in electrical activity similar to that reported for pulse annealed implanted layers occurs with any subsequent heat treatment. A resistive region, found at the surface of the profile, can be circumvented through additionally heating the GaAs thermally during the pulse diffusion and reducing the rapidity of the quench.
Threshold Energy Density for Pulsed Laser Annealing of Silicon
Authors: Hoonhout Dick , Saris Frans 
Published: March 2011

ABSTRACTWe have made a systematic investigation of the threshold energy density for recrystallization of ion-implanted silicon by Q-switched laser irradiation as function of thickness of the disordered layer, temperature during implantation, type and dose of implanted impurity, laser wavelength, and substrate orientation. Most results have been obtained with a Q-switched ruby laser. A linear dependence of the threshold on layer thickness (in the region of 60–300 nm) was found for arsneic-implanted silicon, but not for silicon-implanted silicon. For an amorphous layer thickness of 200 nm we found very little dependence of the threshold on type of dopant. In the case of the Nd:YAG laser, however, the lowest threshold was observed for column VI elements, the highest for column IV elements and intermediate and equal thresholds for the elements from column III and B. The influence of temperature during implantation was found to be small, but the threshold appeared to be different for (100)- and (111)- oriented substrates.
C-V and Capacitance Transient Analysis of Self-Implanted Amorphous Si Layers Regrown by Swept-Line Electron Beam (Sled) Annealing
Authors: Soda K. J. , Dejule R. Y. , Streetman B. G. 
Published: March 2011

ABSTRACTIt is demonstrated that swept-line electron beam (SLEB) annealing can be successfully employed to recrystallize relatively deep (∼0.5 μm) Si-implanted amorphous silicon layers. DLTS and C-V analysis of these layers show significant reductions in concentration of residual defects and magnitude of dopant redistribution effects. For comparison, similar data for furnace annealed material is also presented.
Silicon Bipolar Transistors Fabricated using Ion Implantation and Laser Annealing
Authors: Natsuaki Nobuyoshi , Miyazaki Takao , Ohkura Makoto , Nakamura Toru , Tamura Masao , Tokuyama Takashi 
Published: March 2011

ABSTRACTBipolar transistors with laser annealed base and emitter, as well as those with furnace annealed base and laser annealed emitter, have been successfully fabricated using Q-switched ruby laser pulse irradiation. The performance of laser asannealed transistors is rather poor. However, it can be improved, to some extent, by relatively low temperature furnace annealing after laser irradiation. DC and RF characteristics of laser annealed transistors are presented in conjunction with laser irradiation effects on the characteristics of conventionally fabricated transistors.
Laser-Induced Solid Phase Epitaxy of Silicon Deposited Films
Authors: Roth J.A. , Olson G.L. , Kokorowski S.A. , Hess L.D. 
Published: March 2011

ABSTRACTA comparative study of solid phase epitaxy (SPE) of deposited and ion-implanted amorphous Si films was conducted with the use of a newly developed laser technique. The effects of interface contaminants and contaminants distributed within a deposited film on the rate of SPE and final crystal quality are reported. In the absence of impurities, deposited Si films crystallize at the same rate as ion-implanted layers and yield epitaxial films with comparable crystal quality. The presence of impurities in deposited films at the interface or distributed within the film can severely retard the SPE growth, causing several deleterious effects which ultimately degrade the film quality. These effects are more severe at high temperatures.
Laser Crystallization of Deposited Silicon Films
Authors: Celler G. K. , Leamy H. J. , Aspnes D. E. , Doherty C. J. , Sheng T. T. , Trimble L. E. 
Published: March 2011

ABSTRACTSilicon layers evaporated on crystalline Si have been crystallized by Q-switched Nd:YAG laser irradiation. A strong correlation was observed between the density of a-Si films and the quality of the epitaxial regrowth from the liquid phase. Dense films crystallized epitaxially in a wide range of laser energy densities. Layers with 20% lower density, as determined by spectroscopic ellipsometry, had higher crystallization thresholds and suffered from severe pitting of the surface. Coalescence of the excess void volume into microbubbles, stabilized by gaseous contaminants, is responsible for the surface degradation.In polycrystalline films on amorphous insulating substrates laser melting changes the grain distribution. Rapid melting and solidification of small diameter spots creates concentric rings of large crystallites. This characteristic pattern is explained by a simple model, based on the kinetics of crystallization.
Laser Induced Controlled Nucleation and Growth Process For Large Grained Polycrystalline Silicon
Authors: Danforth S.C. , Van Gieson F. , Haggerty J.S. , Kohatsu I. 
Published: March 2011

ABSTRACTResearch on a new process is described which utilized a laser to achieve controlled crystallization of amorphous Si thinfilms for photovoltaic applications. Amorphous Si films are deposited on suitable substrates using RF sputtering. A laser is used to inoculate these films with crystalline embryos at specific locations. These embryos should then grow in a controlled atmosphere annealing furnace under conditions optimized to maintain the nucleation rate at zero and the transformation rate (from amorphous to crystalline silicon) at a maximum value. The result will be a polycrystalline silicon film with a large grain size to film thickness ratio, where the ultimate grain size will be determined by the laser inoculation spacing.
Cw Laser-Recrystallized Polysilicon as A Device-Worthy Material
Authors: Gibbons James F. 
Published: March 2011

ABSTRACTThe basic crystallographic and electronic properties of cw laser recrystallized thin polysilicon films are presented and shown to be suitable for fabrication of MOSFET devices. Devices and simple integrated circuits fabricated to explore the potential of this material have electrical characteristics similar to devices fabricated on single crystal material and offer significant promise for future applications.
Processing and Properties of Cw Laser-Recrystallized Silicon Films on Amorphous Substrates
Authors: Johnson N. M. , Biegelsen D. K. , Moyer M. D. 
Published: March 2011

ABSTRACTCW laser recrystallization has been used to process silicon thin films as an integral step in semiconductor device fabrication. On continuous films of polycrystalline silicon, a silicon-nitride encapsulant is used to control surface morphology during laser recrystallization. For thin films on bulk glass substrates it is necessary to pattern the silicon layer in order to minimize microcracking as well as to control recrystallization. Over single crystal silicon substrates, test devices have been fabricated in silicon islands on dual-dielectric layers. Materials and device evaluation included TEM, current-voltage, capacitance-voltage, and EBIC measurements, and the test devices consisted of p-n junction diodes, MOS capacitors, and MOS field-effect transistors.
Laser Induced Crystal Growth of Silicon Islands on Amorphous Substrates
Authors: Biegelsen D. K. , Johnson N. M. , Bartelink D. J. , Moyer M. D. 
Published: March 2011

ABSTRACTThe importance of controlled lateral heat flow in the growth of single crystal silicon islands on amorphous substrates is demonstrated. In one approach the thermal profile on and around the islands is determined by varying the optical absorption with a variety of thin film structures. In another, beam spot shaping is used. Competitive nucleation is suppressed and continued in-plane epitaxial zone growth is enhanced. In this way we are able to produce single crystal islands 20μm wide and >20μm long. Routine production of such islands would enable new thin film transistor technologies.
Laser Growth of Thin Silicon Crystals in Patterned Structures
Authors: Fastow R. M. , Leamy H. J. , Celler G. K. , Wong Y. H. , Doherty C. J. 
Published: March 2011

ABSTRACTBeam processing can be applied to thin, polycrystalline silicon films on amorphous substrates to: a( increase grain size, b( produce single, isolated crystals, and c( to produce oriented single crystals. Specific methods for these tasks are outlined. Crystal growth and heat flow consideration appropriate to each are presented.
Beam Induced Reactions in Metal-Film Systems
Authors: Lau S. S. , Mäenpää Martti , Mayer James W. 
Published: March 2011

ABSTRACTPulsed beams (laser, electron, or ion) and ion beams (ion beam mixing) have been used to induce structural and compositional changes in metal-metal and metal-semiconductor thin-film structures. Metastable crystalline and amorphous phases have been formed. Although ultra fast quenching occurs with both techniques, metastable phases are formed by quenching from the liquid with pulsed beams and from the solid-phase with ion-induced reactions. With both techniques metastable phases can be formed over a broader compositional range than with conventional melt-quench methods.
Laser Irradiation of Nickel: Defect Structures and Surface Alloying
Authors: Buene L. , Jacobson D.C. , Nakahara S. , Poate J.M. , Draper C.W. , Hirvonen J.K. 
Published: March 2011

ABSTRACTSurface layers of Ni crystals have been melted with Q-switched Nd-YAG laser radiation. The epitaxially regrown surface layers show significant differences between 〈100〉 and 〈111〉 crystals cut from the same boule. The 〈100〉 crystals exhibit a dislocation cell structure with a dislocation density of l011 - 1012 cm-2. The 〈111〉 crystals contain a laterally uniform dislocation network resulting in a much higher dislocation density for the 〈111〉 surface. The elements Ag, Au, Pd, Sn and Ta have been implanted into Ni single crystals at surface concentrations of up to 20 at %. All the as- implanted systems demonstrate solid solubility. We have used these implanted systems to study the alloys formed by laser melting of Ni. In all systems, with the exception of Ag, 100% of the atoms are trapped on lattice sites.
Pulsed Laser Mixing of Ni-Au Surface Films on Nickel Substrates
Authors: Pronko P.P. , Wiedersich H. , Seshan K. , Helling A.L. , Lograsso T.A. , Baldo P.M. 
Published: March 2011

ABSTRACTThe melt phase alloying of Ni-Au films on Ni substrates has been studied for rapid quenches following 35 nano-second Q switched ruby laser pulses (0.69μ wavelength) in the energy regime of 0.5 to 3.0 j/cm2. The Ni and Au films were each 200 Å in thickness having been deposited on a polished Ni substrate by standard hot ribbon vapor deposition methods. Data was obtained on pre and post alloyed surface layers using Rutherford backscattering, transmission electron microscopy, and STEM energy dispersive X-ray analysis. The melting and resolidification dynamics of the liquid-solid interface was monitored through finite difference integration of the non-linear heat conduction equation to give temperature profiles, depth of melting and melt front velocities associated with the liquid-solid phase change. Resolidification velocities were typically 15 meters/second with melt depths extending to a few thousand angstroms depending on pulse energy. RBS data confirms that liquid phase diffusion of gold in nickel has occured. TEM analysis reveals the presence of a two phase mixture being composed of nickel rich and gold rich material. Microbeam energy dispersive X-ray analysis indicates the presence of a relatively uniform mixing of these two Phases. Pronounced one dimensional solute segregation was not observed in these specimens, however, overall penetration depths of the gold was somewhat larger for the lower energy densities than for the larger ones. Also, unusual circular cell patterns were observed in the resolidified material, their contrast being enhanced by preferential etching during the TEM specimen polishing procedure.
Velocity and Orientation Dependence of Solute Trapping In Si
Authors: Baeri P. , Foti G. , Poate J. M. , Campisano S. U. , Rimini E. , Cullis A. G. 
Published: March 2011

ABSTRACTThe segregation phenomena of In, Ga and Bi in Si have been investigated as a function of the liquid-solid interface velocity following laser irradiation. The crystallization velocity has been changed within the range 0.8–5 m/s by varying either the substrate temperature during irradiation or the laser pulse duration. The measured interfacial segregation coefficients depend critically on the velocity and on the crystal orientation of the solidifying plane.
Ultra-Short Pulse Laser Annealing
Authors: Gamo Kenji , Murakami Kouichi , Kawabe Mitsuo , Namba Susumu , Aoyagi Yoshinobu 
Published: March 2011

ABSTRACTA single picosecond pulse laser annealing of ion-implanted Si is reviewed as ultra-short pulse laser annealing, comparing them with nanosecond pulse and picosecond-pulse train annealing. In order to clarify the physical mechanism of pulsed laser annealing, the dynamic behavior of the amorphous to crystalline transition has been investigated by means of time-dependent optical reflectivity measurement at 0.63 µm (cw) and 1.06 µm (30-ps pulse itself) under the irradiation of the annealing beam of a single 30-ps laser pulse at 1.06 µm. A tentative model is proposed for explaining the results and further problems which remain to be resolved are discussed.
Transmission Electron Microscopy of II-VI/III-V Semiconductor Heteroepitaxial Interfaces
Authors: Li D. , Otsuka N. , Qiu J. , Glenn J. , Kobayashi M. , Gunshor R. L. 
Published: March 2011

ABSTRACTInterfaces of pseudomorphic (100)ZnSe/GaAs and (100)CdTe/InSb heterostructures grown by molecular beam epitaxy have been studied by transmission electron microscopy. High resolution electron microscope images show dark bands with thicknesses of one or two monolayers at the interfaces. The interfaces appear as bright lines in dark field images of the 200 type reflections, while they become dark lines in dark field images of the 400 type reflections. These observations are explained by assuming the existence of interfaces layers of III2VI3 compounds which have structural vacancies in the sublattices of the group III atoms.
Plasma-Assisted Epitaxial Growth of ZnSe Films In Hydrogen Plasma
Authors: Yamauchi S. , Hariu T. 
Published: March 2011

ABSTRACTPlasma-assisted epitaxy (PAE) was applied to the growth of ZnSe films on (100) GaAs for low temperature epitaxial growth in hydrogen plasma. High purity ZnSe films were successfully grown by the control of hydrogen gas flow rate and VI/II supply ratio. Hydrogen-chloride gas and nitrogen gas mixed in pure hydrogen gas plasma around 2% respectively resulted in the growth of highly conductive n-type layers (630Scm−1 ) and nitrogen-acceptor doped layers (N-acceptor level∼100meV), however, the control of VI/II supply ratio is also very important for the efficient N-acceptor doping. The plasma optical emission spectroscopy indicated that Se-N is composed by the reaction of -ion with SeH (or Se) in hydrogen and nitrogen mixed gas plasma with Se supply.