Pulsed Laser-Induced Amorphization of Silicon Films

1991 ◽  
Vol 235 ◽  
Author(s):  
T. Sameshima ◽  
S. Usui
Keyword(s):  
Grain Size ◽  
Film Thickness ◽  
Silicon Film ◽  
Pulsed Laser ◽  
Temperature Sensing ◽  
Silicon Films ◽  
Molten Silicon ◽  
Quartz Substrates ◽  
Xecl Excimer Laser

ABSTRACTAmorphization of silicon films occurred through homogeneous solidification of molten silicon layers on quartz substrates induced by irradiation with a 30ns-XeCl excimer laser. The crystalline nucleation rate was obtained to be 8×1030m−3s−1. Silicon films were completely amorphized for films thinner than 18nm. Complete amorphizatoin is brought about by reduced grain size and reduced recalescence as the film thickness decreases. Recalescence was observed in situusing transient thermometry with a platinum-temperature-sensing layer when a 15nm-thick silicon film was amorphized.

In Situ Measurement of Pulsed Laser Indxuce Carrier Ceneraticn in Doped Silicon Films

1989 ◽  
Vol 158 ◽  
Author(s):  
T. Saveshimn ◽  
M. Hara ◽  
S. Usui
Keyword(s):  
Silicon Film ◽  
Pulsed Laser ◽  
Processing Temperature ◽  
Molten Silicon ◽  
Carrier Generation ◽  
Laser Doping ◽  
Doped Silicon ◽  
Doping Technique ◽  
Dopant Atoms

ABSTRACTTransient conductance measurements were used to study rapid carrier generation during the laser doping of a silicon film. The movement of the liquid-solid interface was measured and the point of initiation of carrier generation frcn dopant atoms diffused to the molten silicon was determined. It was established that the dopant atais are activated at the nmorent the dopant diffused region solidified. Also, the laser doping technique was used to fabricate polycrystalline silicsn thin film transistors (Poly-Si TFT's) ata processing temperature of 250ºC.

The Effect of Film Thickness and Pulse Duration Variation in Excimer Laser Crystallization of Thin Si Films

1996 ◽  
Vol 452 ◽  
Author(s):  
J. P. Leonard ◽  
M. A. Bessette ◽  
V. V. Gupta ◽  
James S. Im
Keyword(s):  
Energy Density ◽  
Film Thickness ◽  
Partial Melting ◽  
Pulse Duration ◽  
Excimer Laser ◽  
Silicon Film ◽  
Silicon Films ◽  
Laser Crystallization ◽  
Crystal Silicon ◽  
Excimer Laser Crystallization

AbstractRecognizing that the processing window in conventional excimer laser crystallization corresponds mainly to the partial melting regime, and that this can be properly simulated using a one-dimensional model, we investigate numerically the melting and solidification of thin silicon films on SiO2. Here a portion of the silicon film is melted and subsequent vertical solidification is initiated from the lower interface bounding the unmelted region. Upper and lower energy density limits for this regime are calculated for crystal silicon films of thickness 10 to 300 nm, and for pulse duration ranging from 10 to 200 ns. These calculations show that increasing pulse duration requires proportionally more incident energy density to partially melt the film, while decreasing film thickness reduces the range of energy densities over which partial melting can occur. The results are explained in terms of characteristic thermal diffusion distances and the enthalpy change associated with melting. In view of the results we discuss optimization of the conventional excimer laser crystallization and the avoidance of complete melting during the process.

In-Situ Optical Diagnostics During Pulsed-Laser Deposition of Magnetoresistive La-Ca-Mn-O Films on Silicon Substrates

1996 ◽  
Vol 441 ◽  
Author(s):  
P.-J. Kung ◽  
J. E. Cosgrove ◽  
K. Kinsella ◽  
D. G. Hamblen
Keyword(s):  
Film Thickness ◽  
Substrate Temperature ◽  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Pulsed Laser ◽  
Target Surface ◽  
Laser Deposition ◽  
Silicon Substrates ◽  
Ft Ir

AbstractDuring pulsed-laser deposition of La0.67Ca0.33MnO3 films on silicon substrates, a system that consists of visible optical-emission spectroscopy (OES) and Fourier transform infrared (FT-IR) spectroscopy is employed to perform in-situ diagnosis of the laser-induced plume and to monitor the substrate temperature and the film thickness. The effects of oxygen pressure, laser fluence, and distance from the target surface on emission spectra were studied. In FT-IR measurements, the slopes of the reflectance versus wavenumber curves were observed to increase with film thickness and hence with time, which provides end-point detection during the film growth. La0.67Ca0.33MnO3 films with (100), (110), and mixed orientations, depending on the substrate temperature, were deposited on yttria-stabilized zirconia (YSZ) buffered Si(100) and Si(111) substrates. In a magnetic field of 5 T, the maximum magnetoresistance (MR) values of 250% at 195 K and 164% at 140 K were observed in the as-deposited (110) and (100) films, respectively.

In-Situ measurements of plane spacing during electromigration in a passivated AI line

1996 ◽  
Vol 54 ◽  
pp. 242-243
Author(s):  
P.-C. Wang ◽  
I. C. Noyan ◽  
E. G. Liniger ◽  
C.-K. Hu ◽  
G. S. Cargill
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Film Thickness ◽  
Current Flow ◽  
Material Transport ◽  
Solid State Detector ◽  
Strain Measurements ◽  
X Ray ◽  
State Detector

To determine the effect of confinement on the material transport that occurs during electromigration, in-situ x-ray strain measurements were conducted along the length of a passivated Al line that was first heated (in two steps) to 267°C and then subjected to current flow.The specimen geometry used in the experiment is shown in Figure 1. Further details can be obtained from references 1,2. The Al in the line and the contact pads had a grain size of the order of the film thickness (0.5 μm) and exhibited strong 111 texture with a range of ±5 degrees. The W pads also exhibited strong 110 texture and had much finer grain size. The x-ray measurements were carried out on the NSLS X-26C beamline using a focussing tapered capillary for collimating the beam. The irradiated area on the line was a 10μmx10μm square. The Al 111 plane spacing (d111) was measured using white beam (Laue) diffraction with a solid-state detector. This plane spacing was measured at different locations along the line.

Numerical Modeling of High Repetition Rate Pulsed Laser Crystallization of Silicon Films on Glass

2001 ◽  
Vol 685 ◽  
Author(s):  
Jürgen R. Köhler ◽  
Ralf Dassow ◽  
Jürgen H. Werner
Keyword(s):  
Film Thickness ◽  
Repetition Rate ◽  
Strong Dependence ◽  
Silicon Film ◽  
High Repetition Rate ◽  
Silicon Films ◽  
Solidification Velocity ◽  
Laser Crystallization ◽  
High Repetition ◽  
Grain Width

AbstractThis contribution investigates the crystallization behavior of amorphous silicon films on glass by using pulsed lasers with very high repetition rates up to 100 kHz. We determine the influence of the laser repetition rate f and of the film thickness d on the grain width g of the resulting polycrystalline silicon films. Our experimental results indicate a strong dependence of the grain width g on film thickness d as well as on the repetition rate f of the laser. The grain width rises from g = 0.27 µm to g = 3.59 µm if the film thickness increases from d = 50 nm to d= 300 nm and the repetition rate f from f = 20 kHz to 100 kHz. We use a purpose developed two- dimensional finite difference numerical model to calculate the evolution of the temperature in the silicon film and in the glass substrate. An increase of both, the film thickness d, and the repetition rate f decrease the solidification velocity v of the film. A comparison of the solidification velocity vs and the measured grain width g shows a linear correlation.

Study Optical and Structure Properties of Nano ZnO/Cu2O Mixture Prepared by Pulsed Laser Deposition for Application

2020 ◽  
Vol 398 ◽  
pp. 1-7
Author(s):  
Ayad Z. Mohammad
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Film Thickness ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Mixing Ratio ◽  
Energy Band Gap ◽  
Mixing Ratios ◽  
Average Grain Size ◽  
Structure Properties

Nd:YAG laser was used at different number of shots (300, 500, and 700 pulse) to prepare ZnO:Cu2O nanoparticles at mixing ratios of (0.5, 0.7 and 0.9). The optical, structural, morphological and electrical properties of the prepared films were investigated. The energy band gap was found to be (2.5, 3.2 and 3.53 e.v). The crystalline structure showed no impurity peaks indicating that the final product was free from surface impurities. Also, the materials peaks and intensity is present and well identified as the mixing ratio varies. The AFM results for all ratios indicate that as the number of pulses increase, the higher the resulted grain size. The average grain size was between (58.82 nm) to (95.75nm). The J-V characteristics were measured for the prepared solar cells and it was found that the efficiency varied with the mixing ratio and film thickness from 0.29% to 2.38%. F.F varied from 0.28 to 0.25.

MAGNETIC PROPERTIES OF NANOCRYSTALLINE CO-FERRITE FILMS DEPOSITED ON SINGLE-CRYSTAL SiO2 SUBSTRATES USING PULSED LASER DEPOSITION

2008 ◽  
Vol 15 (01n02) ◽  
pp. 71-75 ◽  
Author(s):  
J. H. YIN ◽  
J. DING ◽  
B. H. LIU ◽  
X. S. MIAO ◽  
J. B. YI ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Film Thickness ◽  
Magnetic Anisotropy ◽  
Residual Strain ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Post Annealing ◽  
In Situ Heating ◽  
Ferrite Films

Co-ferrite films were prepared using pulsed laser deposition with both post-annealing and in situ heating processes. Magnetic properties of these films were studied in the function of temperature, film thickness, and substrate. The films using post-annealing processes exhibited isotropic microstructure, and the coercivity showed no obvious magnetic anisotropy and no strong dependence on film thickness. Co-ferrite films using in situ heating exhibited (111) highly textured structure and possessed perpendicular anisotropy as well as large coercivity. The preferential texture and magnetic anisotropy were closely associated with substrate temperature and thickness. Perpendicular Hc over 12.5 kOe was obtained in the 33 nm Co-ferrite film deposited on single crystal quartz substrate at 550°C. The high coercivity and perpendicular coercivity may be attributed to the nanocrystalline grain, textured orientation, and large residual strain in these films since large residual strain may induce strong stress anisotropy.

Sign in / Sign up

Export Citation Format

Share Document