Showing papers on "Ruby laser published in 1980"
TL;DR: In this article, the formation of supersaturated substitutional alloys by ion implantation and rapid liquid phase-epitaxial regrowth induced by pulsed laser annealing has been studied using Rutherford backscattering, ion channeling analysis.
Abstract: The formation of supersaturated substitutional alloys by ion implantation and rapid liquid‐phase‐epitaxial regrowth induced by pulsed laser annealing has been studied using Rutherford backscattering, ion channeling analysis. Group‐III (Ga, In) and group‐V (As, Sb, Bi) dopants have been implanted into single‐crystal silicon at doses ranging from 1×1015 to 1×1017/cm2. The samples were annealed with a Q‐switched ruby laser (energy density ∼1.5 J/cm2, pulse duration ∼15×10−9 sec). Ion channeling analysis shows that laser annealing incorporates these dopants into substitutional lattice sites at concentrations far in excess of the equilibrium solid solubility. Channeling measurements indicate the silicon crystal is essentially defect free after laser annealing. Also values for the maximum dopant concentration (Cmaxs) that can be incorporated into substitutional lattice sites are determined for our annealing conditions. Dopant profiles determined by Rutherford backscattering are compared to model calculations wh...
311 citations
TL;DR: In this article, the levels of C and O surface contaminants were reduced to within the detection limits of Auger electron spectroscopy using pulsed ruby laser radiation and showed that pulsed laser irradiation can be used to prepare atomically clean Si surfaces in remarkably short processing times.
Abstract: Irradiation of single‐crystal silicon with pulsed ruby laser radiation is shown to reduce the levels of C and O surface contaminants to within the detection limits of Auger electron spectroscopy. Similar results were observed following irradiation of Ar sputtered surfaces and surfaces with chemisorbed oxygen. These results show that pulsed laser irradiation can be used to prepare atomically clean Si surfaces in remarkably short processing times.
108 citations
TL;DR: The temporal profiles of the continuum pulses at different wavelengths are studied with a photomultiplier system and are found to have essentially the same halfwidths as the pulse from the exciting Q-switched ruby laser.
Abstract: Recent work has shown that with appropriate targets, laser-produced plasmas provide clean essentially linefree continua suitable for absorption spectroscopy from 40 to 2000 A. A systematic study of the continua emitted by the elements from samarium to ytterbium is reported, and their use in absorption spectroscopy is demonstrated. The temporal profiles of the continuum pulses at different wavelengths are studied with a photomultiplier system and are found to have essentially the same halfwidths as the pulse from the exciting Q-switched ruby laser (~25 nsec). Pulse heights are shown to be reproducible to 15% or better. Ambient gases, at least at pressures up to several Torr, do not affect the emission mechanism. A comparison with other continuum sources at XUV wavelengths (i.e., BRV, synchrotron) is made, and possible future developments are outlined.
93 citations
TL;DR: In this paper, single crystal Si films have been epitaxially grown from chemical vapor-deposited poly-Si films from 2000 to 6000 A on (100) Si substrates by Q-switched ruby laser pulse irradiation of 25 ns duration at power densities above 2.0 J/cm2.
Abstract: Single crystal Si films have been epitaxially grown from chemical vapor-deposited poly-Si films from 2000 to 6000 A thick on (100) Si substrates by Q-switched ruby laser pulse irradiation of 25 ns duration at power densities above 2.0 J/cm2. When a poly-Si film deposited on the thermally grown SiO2 comes in contact with the substrate at the oxide window area, epitaxial growth first occurs at the window area. It then propagates in the lateral direction over the SiO2 up to a distance of 1.2 µm from the oxide edge. In Si films grown on SiO2, dislocations and stacking faults lying nearly in the directions remain.
92 citations
TL;DR: In this paper, the authors used x-ray Bragg reflection profiles from implanted, laser annealed silicon to obtain the strain distribution in the implanted layer as a function of depth.
Abstract: The strain distribution in boron implanted, laser annealed silicon has been investigated using x‐ray Bragg reflection profiles. The 400 Bragg reflection profile from implanted, laser annealed silicon was analyzed, using the dynamical theory of scattering for distorted crystals, to obtain the strain distribution in the implanted layer as a function of depth. The depth distribution of the strain for an implantation dose of 1×1016 35 keV B+/cm2, followed by a 1.6 J/cm2 ruby laser pulse, was found to have a magnitude of −5.8×10−3 near the surface and was found to decrease rapidly for depths greater than 0.2 μm. The shape of the depth distribution of the strain was found to be essentially the same as that for the boron distribution after laser annealing.
77 citations
41 citations
TL;DR: In this paper, a theoretical investigation is made into the ionisation of helium, at pressures of 1800-17000 Torr (024-227 MPa) by ruby laser radiation of pulse-length 40 ns.
Abstract: A theoretical investigation is made into the ionisation of helium, at pressures of 1800-17000 Torr (024-227 MPa) by ruby laser radiation of pulse-length 40 ns It is shown that, when the variation of electron energy gain in elastic collisions is taken into account, the agreement between computed and experimental breakdown threshold intensities is improved by a factor of 10 compared with calculations in which only the mean energy gain is computed The agreement is also improved significantly by incorporating the collisional and multiphoton ionisation of excited helium atoms
31 citations
TL;DR: In this paper, the (111, (110), and (100) faces of Si were studied following various surface preparations including exposure to ruby laser pulses, and the surface preparations involving laser irradiation were shown to have several advantages over other methods.
Abstract: Q‐switched lasers are potentially a useful tool for the preparation of surfaces in UHV for surface analysis. The (111), (110), and (100) faces of Si were studied following various surface preparations including exposure to ruby laser pulses. Surface preparations involving laser irradiation were shown to have several advantages over other methods.
29 citations
TL;DR: In this article, the solubility of several dopants (Sb, Ga, Bi, In) in laser treated silicon has been investigated, and the results were in good agreement with those calculated from a simple model based on phase diagram considerations.
Abstract: The solubility of several dopants (Sb, Ga, Bi, In) in laser treated silicon has been investigated. The dopants were introduced by vacuum deposition followed by ruby laser irradiation. Their solubility was determined by Rutherford backscattering spectroscopy measurements in channelling and random conditions. In all cases, a maximum solubilityCS*, much higher than the equilibrium solubility limitCS0 and independent of the pulsed laser energy density, was found. The values obtained are in good agreement with those calculated from a simple model based on phase diagram considerations, using the relationship:
$$C_S^* = \frac{{C_S^0 }}{{k_0 }}k^* ,$$
26 citations
TL;DR: In this article, low energy electron diffraction observations from Si single crystals following irradiation with a pulsed ruby laser show that the laser annealing induced epitaxial regrowth process extends to the outermost layer of the crystal.
26 citations
TL;DR: In this article, the properties of the annealed films were studied as a function of laser energy by means of electron microscopy, photoluminescence and infra-red absorption.
Abstract: Glow discharge amorphous silicon layers have been annealed using a Q-switched ruby laser. The properties of the annealed films were studied as a function of laser energy by means of electron microscopy, photoluminescence and infra-red absorption. The changes in structure, hydrogen content, band-gap and density of states in the annealed layers are discussed. It is found that there are considerable similarities between the amorphous and the annealed material.
TL;DR: In this paper, a GaAs single-crystals wafers are implanted at room temperature with 400-keV Te + ions to a dose of 1×10^15 cm^2 to form an amorphous surface layer.
Abstract: GaAs single-crystals wafers are implanted at room temperature with 400-keV Te + ions to a dose of 1×10^15 cm^–2 to form an amorphous surface layer. The recrystallization of this layer is investigated by backscattering spectrometry and transmission electron microscopy after transient annealing by Q-switched ruby laser irradiation. An energy density threshold of about 1.0 J/cm^2 exists above which the layer regrows epitaxially. Below the threshold the layer is polycrystalline; the grain size increases as the energy density approaches threshold. The results are analogous to those reported for the elemental semiconductors, Si and Ge. The threshold value observed is in good agreement with that predicted by the simple model successfully applied previously to Si and Ge.
TL;DR: In this paper, the differences between the liquid and solid phase annealing mechanisms of the pulsed-laser and scanned-electron-beam methods, respectively, are highlighted.
Abstract: Silicon implanted with As+, P+, or B+ ions has been annealed by the multiple‐scan electron beam method and by use of pulsed radiation from a Q‐switched ruby laser. Electron microscope examination of specimen cross section gives direct comparison of the initial implantation damage with the structures produced by the different annealing methods. Sample electric conductivities after annealing are also compared. This work highlights the differences between the liquid‐ and solid‐phase annealing mechanisms of the pulsed‐laser and scanned‐electron‐beam methods, respectively.
TL;DR: In this paper, an optical filter is employed to transport a 15-ns light pulse from a high power ruby laser for precise triggering of a gas filed high voltage spark gap, and the overall throughput efficiency of the optical system was measured as 62 percent.
Abstract: An optical filter is employed to transport a 15-ns light pulse from a high power ruby laser for precise triggering of a gas filed high voltage spark gap. The maximum power density that can be transmitted by the fiber is limited to 6 × 1012 W/m2 above which laser induced damage occurs on the fiber entrance face. The overall throughput efficiency of the optical system was measured as 62 percent. Results are presented for the switching delay time and associated jitter for various mixtures of A and N2 gas, and as a function of the voltage across a pulse-charged Blumlein generator gap. Pulse charging of the Blumlein generator was accomplished by a three-stage Marx generator, resulting in output voltages up to 250 kV. It was conclusively demonstrated that an optical fiber will transport a sufficiently intense laser pulse to evince subnanosecond jitter in the triggering of a pressurized gas switch under the conditions studied.
TL;DR: In the early 1970's, it became experimentally feasible to use high-powered infrared laser technology in chemical processes as mentioned in this paper, and the period since then has seen intense and systematic study of atomic and molecular processes.
Abstract: Proposals for controlling or inducing chemical reactions with laser light have been around almost as long as lasers themselves. Immediately after Theodore Maiman's invention of the ruby laser in 1960 and Ali Javan, William Bennett and Donald Herriott's invention of the helium–neon gas laser in 1961 suggestions for using this new type of light source in chemical processes followed. The proposals resulted essentially from adapting already well‐known principles of photochemistry. Yet almost no research employing lasers in chemistry was done for ten years. Not until tunable lasers and high‐powered infrared lasers arrived at the end of the 1960's and in the early 1970's did laser chemistry become experimentally feasible, and the period since then has seen intense and systematic study of atomic and molecular processes. Of particular interest are those selective processes applicable to laser isotope separation, such as the work on carbon isotopes carried out in the apparatus shown in figure 1 and discussed later...
TL;DR: In this article, the two-photon absorption (TPA) coefficient of various semiconductors is determined with a Q-switched Ruby-laser (h vL = 1.785 eV).
Abstract: With aQ-switched Ruby-laser (h vL=1.785 eV), the two-photon absorption (TPA) coefficient of various semiconductors is determined. The gap energy,Eg, of these substances is lying in the range ofh vL
TL;DR: The role of dissolved oxygen supersaturation, which seems to be generated by laser irradiation of airexposed samples, is discussed briefly in the light of the use of laser annealing techniques for electronic device fabrication.
Abstract: Ion-implanted Si wafers were irradiated in air with a Q-switched ruby laser and then isochronally annealed between 450 and 850 degrees C. Within the depth corresponding to the melted thickness, a considerable amount of alpha-quartz was detected in the 700-800 degrees C range. Copper precipitation was observed associated with alpha-quartz formation. The role of a dissolved oxygen supersaturation, which seems to be generated by laser irradiation of air-exposed samples, is discussed briefly in the light of the use of laser annealing techniques for electronic device fabrication.
TL;DR: In this paper, it was shown that Brillouin scattering occurs in short spikes, sometimes early in the pulse, sometimes delayed by as much as 700 nsec. This time behavior depends critically on the state of pre-ionization and is explained by the evolution of a laser-driven ionization wave.
Abstract: Stimulated Brillouin scattering at 180° and sidescatter at 90° are observed when CO2 laser light is incident on an arc‐pre‐ionized, underdense plasma target. Scattering occurs in short spikes, sometimes early in the pulse, sometimes delayed by as much as 700 nsec. This time behavior depends critically on the state of pre‐ionization and is explained by the evolution of a laser‐driven ionization wave. Using ruby laser interferometry, it is possible to infer the sources of backscatter and sidescatter within this disturbance. In addition, by using a smooth input pulse, it is found that the spikiness of Brillouin scatter is not due solely to mode beating in the input beam.
TL;DR: In this article, a new technique based on deposition of metallic film at room temperature followed by laser irradiation, for the formation of Ohmic contacts on semiconducting oxides, has been developed.
Abstract: A new technique based on deposition of metallic film at room temperature followed by laser irradiation, for the formation of Ohmic Contacts on semiconducting oxides, has been developed. Aluminum or nickel film about 1 μm thick was deposited on n‐type polycrystalline barium titanate (BaTi03) substrates and irradiated with Q‐switched ruby laser pulses. This technique produces low‐resistance Ohmic contacts which do not age and remain stable over a wide temperature range.
TL;DR: In this paper, the authors calculated multiphoton ionisation cross sections for ground state caesium by linearly polarised light in frequency ranges containing the tuning range of the ruby laser, the Nd glass laser and its first harmonic.
Abstract: Non-resonant k-photon ionisation cross sections may be calculated by kth order perturbative treatment. This method is generally considered to be good when the detuning from the closest resonance is much larger than the expected shift and width of this resonance. The aim of this paper is to discuss the validity of this criterion for several realistic cases. By diagonalising an effective Hamiltonian built on a few quasi-resonant states, we have calculated multiphoton ionisation cross sections for ground state caesium by linearly polarised light in frequency ranges containing the tuning range of the ruby laser, the Nd glass laser and its first harmonic. The study is carried out up to an intensity of 1011 W cm-2.
TL;DR: In this paper, a systematic study of this effect has been performed using SIMS, RBS, Hall and sheet resistance measurements, which showed that the increase of electrically active phosphorus after laser treatment is not only related to the dissolution of precipitates but also to the dissociation of P+V−- pairs.
Abstract: The concentration of electrically active phosphorus which can be introduced into silicon by conventional high temperature diffusion is limited to about 4 × 1020 cm−3, Phosphorus in excess of this concentration is inactive because it is precipitated and/or paired with doubly charged vacancies according to the Fair-Tsai model. It has been shown recently that this phosphorus can be partly or totally reactivated by irradiation with high energy (1 J/cm2) ruby laser pulses of short duration and that more heavily doped junctions can be realized by such treatment. In this work, a systematic study of this effect has been performed using SIMS, RBS, Hall and sheet resistance measurements. The influence of the diffusion and irradiation conditions and also of post irradiation thermal treatment has been considered. The results show that the increase of electrically active phosphorus after laser treatment is not only related to the dissolution of precipitates but also to the dissociation of P+ V−- pairs.
TL;DR: In this article, the epitaxial regrowth of argon-implanted self-implantation-produced amorphous silicon under Q-switched ruby laser pulses is reported.
Abstract: The epitaxial regrowth of argon‐implanted self‐implantation‐produced amorphous silicon under Q‐switched ruby laser pulses is reported. It is shown that pulse annealing succeeds in producing epitaxial regrowth in the present case where equilibrium thermal annealing fails. A highly porous layer filled with spherical voids is observed by transmission electron microscopy (TEM). Four‐point probe measurements of the annealed layers exhibit a very high sheet resistance. The electrical properties are explained in terms of the unique microstructure of the pulse annealed layer.
TL;DR: In this article, Bismuth-implanted zinc telluride has been annealed by high-power ruby laser pulses, and channeling and reflectivity measurements indicate a progressive reordering with increasing energy density.
Abstract: Bismuth‐implanted zinc telluride has been annealed by high‐power ruby laser pulses. Owing to its band gap (2.28 eV) the crystalline ZnTe is transparent to the ruby radiation while the implanted material is absorbing, leading to selective annealing. Channeling and reflectivity measurements indicate a progressive reordering with increasing energy density.
TL;DR: In this article, Ruby laser pulses of 1.5−2.5 J were used to dissolve defect nuclei in {100} and {111} silicon surfaces implanted with (1−5)×1014 P cm−2 and (1 −1.5 −2 J) respectively.
Abstract: Ruby laser pulses of 1.5–2.5 J cm−2 were shown to be effective in dissolving defect nuclei in {100} and {111} silicon surfaces implanted with 1014–1015 B cm−2 and (1–5)×1014 P cm−2. No melting and only partial electrical activation appear to occur. A sequential moderate thermal anneal, 10 min at 1000 °C, results in full electrical activation. A {111} silicon surface, made amorphous by an ion implantation of 5×1014 P cm−2 was electrically activated and completely cleared of defect nuclei without apparent melting by preceding the laser anneal by a two‐step thermal anneal (30 min at 550 °C, 10 min at 1000 °C). The mechanism of pulse laser annealing of nonamorphous ion‐implanted surfaces is discussed.
TL;DR: In this article, the annealing effect of laser pulses from ruby and neodymium glass lasers on ion implanted 57Fe in silicon is investigated by Mossbauer conversion electron spectroscopy.
Abstract: The annealing effect of laser pulses from ruby and neodymium glass lasers on ion implanted 57Fe in silicon is investigated by Mossbauer conversion electron spectroscopy. For light pulses (≈ 70 ns duration time) from a ruby laser with a power density of 1.5 J/cm2, the Mossbauer spectrum changes drastically upon irradiation. After the irradiation, a quadrupole doublet is observed. This is interpreted to be due to the precipitation of FeSi compounds of approximately FeSi2 composition. From anodic stripping of surface layers it is found that these precipitates are formed in a shallow surface layer of ⪅ 200 A. The results are explained by the assumption that a surface layer of the silicon is molten. For light pulses from a Nd laser (≈ 100 ns duration time), the same result as for a ruby laser is obtained for power densities ⪆ 10 J/cm2. For lower power densities the Mossbauer spectra change only slightly but the implant with an average depth of ≈ 650 A is found to move towards the surface to an average depth of ≈ 300 A.
01 Jan 1980
TL;DR: In this article, a method for the simultaneous production of several bubbles in a liquid is presented, where computer generated Fresnel and Fourier transform binary phase holograms formed in photoresist are used to split a ruby laser pulse.
Abstract: A new holographic method for the simultaneous production of several bubbles in a liquid is presented. Computer generated Fresnel and Fourier transform binary phase holograms formed in photoresist are used to split a ruby laser pulse. Holograms yielding systems of two or five bubbles each in silicone oil have been successfully employed in the laboratory. Preliminary results are given.
TL;DR: In this article, a ruby laser sytem in periodically Q-switched operation was used for Thomson scattering from a tokamak plasma, and the laser delivered about 25 equidistant pulses of more than 10 MW peak power during the 1-ms flashlamp discharge.
Abstract: A ruby laser sytem in periodically Q‐switched operation was used for Thomson scattering from a tokamak plasma. The laser delivers about 25 equidistant pulses of more than 10 MW peak power during the 1‐ms flashlamp discharge. Electron density and temperature of the plasma were recorded as a function of time during the pulse sequence. The repetitively Q‐switched system has been used to measure temperature and density development during a disruptive instability.
TL;DR: In this article, the use of laser microspectral analysis for the quantitative measurement of silicon and chromium, present in concentrations as low as 0.08% in mild steels, is investigated.
Abstract: The use of laser microspectral analysis for the quantitative measurement of silicon and chromium, present in concentrations as low as 0.08% in mild steels, is investigated. A comparison is made between the use of Q-switched and normal ruby laser operation, both spark assisted. Time integrated electron temperature measurements of iron plasmas and time resolved spectra of A1 plasmas are presented and used to determine if the ‘local thermodynamic equilibrium’ model applies to these laser initiated plasmas.
TL;DR: Deep level transient spectroscopy (d.l.t.s) has been applied to the study of deep levels in GaAs following post-implantation annealing using a Q-switched ruby laser as mentioned in this paper.
Abstract: Deep level transient spectroscopy (d.l.t.s.) has been applied to the study of deep levels in GaAs following post-implantation annealing using a Q-switched ruby laser. High concentrations (> 1015 cm?3) of deep trapping levels are observed in the laser melt region using a forward-bias voltage pulse.
TL;DR: In this article, the XUV spectra emitted by plasma produced by focusing a ruby laser on plane targets of carbon and beryllium have been observed with a novel stigmatic spectrograph fitted with a toroidal mirror.