Measurement of Fast Melting and Regrowth Velocities in Picosecond Laser Heated Silicon

1983 ◽  
Vol 13 ◽  
Author(s):  
P. H. Bucksbaum ◽  
J. Bokor
Keyword(s):  
Picosecond Laser ◽  
Liquid Films ◽  
Heat Diffusion ◽  
Incident Laser ◽  
Time Resolved ◽  
Light Pulses ◽  
Incident Laser Intensity ◽  
Krf Excimer Laser ◽  
Laser Heated ◽  
Melting Experiment

ABSTRACTFast regrowth of amorphous silicon from liquid silicon films has been directly observed in a time resolved picosecond laser melting experiment. Liquid films up to 100 nm thick were formed on crystalline substrates with 15 picosecond 248 nm pulses from a KrF* excimer laser. The film thickness as a function of time was probed directly by observing attenuation of 1.64 pm 15 psec light pulses transmitted through the melt. Melting and regrowth velocities were compared to a heat diffusion model, and evidence for melt undercooling was observed. The resolidified silicon was amorphous at all values of incident laser intensity.

Measurement of Ultrafast Melting and Regrowth Velocities in Pulsed Laser Heated Silicon

1983 ◽  
Vol 23 ◽  
Author(s):  
Philip H. Bucksbaum ◽  
Jeffrey Bokor
Keyword(s):  
Laser Fluence ◽  
Pulsed Laser ◽  
Liquid Films ◽  
Heat Diffusion ◽  
Solid Interface ◽  
Direct Measurements ◽  
Laser Heated ◽  
Good Agreement

ABSTRACTDirect measurements of the liquid/solid interface veiocity have been made during both melt-in and regrowth for puised (20 psec) ultraviolet lasei irradiation or crystailine silicon. The regrowth velocity was 25 m/sec, independent or laser fluence. Regrowtn velocities of 50 to 100 m/sec are expected from heat diffusion calculations which neglect undercooling, whereas the inclusion of an appropriate undercooling curve brings the calculation into good agreement with the data. Tne liquid films produced were up to 40 nm thick and were fully amorphized on resoliaificaion.

Picosecond Laser-Induced Solid-Liquid Phase Transformations in Gallium Arsenide and Silicon

1988 ◽  
Vol 100 ◽  
Author(s):  
B. Danielzik ◽  
P. Harten ◽  
K. Sokolowski-Tinten ◽  
D. von der Linde
Keyword(s):  
Gallium Arsenide ◽  
Liquid Phase ◽  
Phase Transformations ◽  
Picosecond Laser ◽  
Time Resolved ◽  
Velocity Increase ◽  
Melting Threshold ◽  
A New Technique ◽  
Solid Liquid ◽  
Laser Heated

ABSTRACTMelt-in velocities of picosecond laser-heated Si and GaAs were obtained from optical reflectivity measurements. We observed a velocity increase from about 100 m/s near the melting threshold to many hundred m/s at higher fIuences. With a new technique for picosecond time-resolved observation of atomic desorption we have been able to resolve the evaporation of Ga.

Root Cause Analysis Techniques Using Picosecond Time Resolved LADA

2014 ◽  
Author(s):  
Dan Bodoh ◽  
Kent Erington ◽  
Kris Dickson ◽  
George Lange ◽  
Carey Wu ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Picosecond Laser ◽  
Root Cause Analysis ◽  
Fault Isolation ◽  
Time Resolved ◽  
Cause Analysis ◽  
Root Cause ◽  
Design And Manufacturing ◽  
Multiple Interactions ◽  
Established Technique

Abstract Laser-assisted device alteration (LADA) is an established technique used to identify critical speed paths in integrated circuits. LADA can reveal the physical location of a speed path, but not the timing of the speed path. This paper describes the root cause analysis benefits of 1064nm time resolved LADA (TR-LADA) with a picosecond laser. It shows several examples of how picosecond TR-LADA has complemented the existing fault isolation toolset and has allowed for quicker resolution of design and manufacturing issues. The paper explains how TR-LADA increases the LADA localization resolution by eliminating the well interaction, provides the timing of the event detected by LADA, indicates the propagation direction of the critical signals detected by LADA, allows the analyst to infer the logic values of the critical signals, and separates multiple interactions occurring at the same site for better understanding of the critical signals.

Time-Resolved Explosion of Intense-Laser-Heated Clusters

2003 ◽  
Vol 90 (2) ◽  
Author(s):  
K. Y. Kim ◽  
I. Alexeev ◽  
E. Parra ◽  
H. M. Milchberg
Keyword(s):  
Intense Laser ◽  
Time Resolved ◽  
Laser Heated

Nanosecond time-resolved Raman spectroscopy of laser-heated silicon

1984 ◽  
Vol 30 (8) ◽  
pp. 4850-4852 ◽  
Author(s):  
G. Wartmann ◽  
M. Kemmler ◽  
D. von der Linde
Keyword(s):  
Raman Spectroscopy ◽  
Time Resolved ◽  
Laser Heated

Numerical Study of Temperature and Incandescence Intensity of Nanosecond Pulsed-Laser Heated Soot Particles at High Pressures

2005 ◽  
Author(s):  
Fengshan Liu ◽  
David R. Snelling ◽  
Gregory J. Smallwood
Keyword(s):  
Soot Particle ◽  
High Pressures ◽  
Particle Diameter ◽  
Aggregate Size ◽  
Primary Particle Diameter ◽  
Time Resolved ◽  
Soot Particles ◽  
Nanosecond Pulsed Laser ◽  
Primary Particles ◽  
Laser Heated

Histories of temperature and incandescence intensity of nanosecond pulsed-laser heated soot particles of polydispersed primary particles and aggregate sizes were calculated using an aggregate-based heat transfer model at pressures from 1 atm up to 50 atm. The local gas temperature, distributions of soot primary particle diameter and aggregate size assumed in the calculations were similar to those found in an atmospheric laminar diffusion flame. Relatively low laser fluences were considered to keep the peak particle temperatures below about 3400 K to ensure negligible soot particle sublimation. The shielding effect on the heat conduction between aggregated soot particles and the surrounding gas was accounted for based on results of direct simulation Monte Carlo calculations. After the laser pulse, the temperature of soot particles with larger primary particles or larger aggregates cools down slower than those with smaller primary particles or smaller aggregates due to smaller surface area-to-volume ratios. The effective temperature of soot particles in the laser probe volume was calculated based on the ratio of thermal radiation intensities of the soot particle ensemble at 400 and 780 nm. Due to the reduced mean free path of molecules with increasing pressure, the heat conduction between soot particles and the surrounding gas shifts from the free-molecular to the transition regime. Consequently, the rate of conduction heat loss from the soot particles increases significantly with pressure. The lifetime of laser-induced incandescence (LII) signal is significantly reduced as the pressure increases. At high pressures, the time resolved soot particle temperature is very sensitive to both the primary particle diameter and the aggregate size distributions, implying the time-resolved LII particle sizing techniques developed at atmospheric pressure lose their effectiveness at high pressures.

Time‐resolved x‐ray conversion efficiencies of laser‐heated plasmas

1988 ◽  
Vol 59 (8) ◽  
pp. 1801-1803 ◽  
Author(s):  
F. Ze ◽  
R. L. Kauffman ◽  
B. Lasinski ◽  
L. Suter ◽  
S. Langer ◽  
...  
Keyword(s):  
Time Resolved ◽  
X Ray ◽  
Laser Heated ◽  
Conversion Efficiencies

Dynamics of Ultrafast Laser Induced Damage in Single Crystal Ni-based Superalloy During Machining

2006 ◽  
Vol 980 ◽  
Author(s):  
Joel P. McDonald ◽  
Shuwei Ma ◽  
John A. Nees ◽  
Tresa M. Pollock ◽  
Steven M. Yalisove
Keyword(s):  
Shock Wave ◽  
Laser Fluence ◽  
Ultrafast Laser ◽  
Laser Exposure ◽  
Mechanical Shock ◽  
Incident Laser ◽  
Machining Time ◽  
Time Resolved ◽  
Pump Probe ◽  
Laser Induced Damage

AbstractPump-probe imaging of femtosecond pulsed laser ablation was performed to investigate the mechanical shock induced on an intermetallic superalloy CMSX-4 during femtosecond laser machining. Time resolved shadowgraphic images were collected of the shock wave produced in the air above the target following laser exposure (0-10.3 nanoseconds). The dimensions of the shock wave were measured as a function of delay time and laser fluence (1.27 J/cm2 - 62.8 J/cm2). Time-resolved shadowgraphic images of the ablation event will be presented, and the corresponding damage morphology as a function of incident laser fluence will be discussed.

scholarly journals Multiscale electronic and thermomechanical dynamics in ultrafast nanoscale laser structuring of bulk fused silica

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Madhura Somayaji ◽  
Manoj K. Bhuyan ◽  
Florent Bourquard ◽  
Praveen K. Velpula ◽  
Ciro D’Amico ◽  
...  
Keyword(s):  
Rarefied Gas ◽  
Void Formation ◽  
Fused Silica ◽  
Heat Diffusion ◽  
Time Resolved ◽  
Plasma Decay ◽  
Laser Structuring ◽  
Decay Times ◽  
Transient Plasma ◽  
Densified Glass

Abstract We describe the evolution of ultrafast-laser-excited bulk fused silica over the entire relaxation range in one-dimensional geometries fixed by non-diffractive beams. Irradiation drives local embedded modifications of the refractive index in the form of index increase in densified glass or in the form of nanoscale voids. A dual spectroscopic and imaging investigation procedure is proposed, coupling electronic excitation and thermodynamic relaxation. Specific sub-ps and ns plasma decay times are respectively correlated to these index-related electronic and thermomechanical transformations. For the void formation stages, based on time-resolved spectral imaging, we first observe a dense transient plasma phase that departs from the case of a rarefied gas, and we indicate achievable temperatures in the excited matter in the 4,000–5,500 K range, extending for tens of ns. High-resolution speckle-free microscopy is then used to image optical signatures associated to structural transformations until the evolution stops. Multiscale imaging indicates characteristic timescales for plasma decay, heat diffusion, and void cavitation, pointing out key mechanisms of material transformation on the nanoscale in a range of processing conditions. If glass densification is driven by sub-ps electronic decay, for nanoscale structuring we advocate the passage through a long-living dense ionized phase that decomposes on tens of ns, triggering cavitation.

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