Rear surface spallation on single-crystal silicon in nanosecond laser micromachining

Journal Article · Sun May 15 04:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1896095· OSTI ID:20709665

Ren, Jun; Orlov, Sergei S; Hesselink, Lambertus ^[1]

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1. Solid State Physics Laboratory, Electrical Engineering Department, Stanford University, California 94305 (United States)

Rear surface spallation of single-crystal silicon under 5-ns laser pulse ablation at intensities of 0.6-60 GW/cm{sup 2} is studied through postablation examination of the ablated samples. The spallation threshold energy and the spallation depth's dependences on the energy and target thickness are measured. From the linear relation between the spallation threshold energy and the target thickness, an estimation of the material spall strength around 1.4 GPa is obtained, in reasonable agreement with the spall strength estimation of 0.8-1.2 GPa at a strain rate of 10{sup 7} s{sup -1} using Grady's model for brittle materials. The experiment reveals the internal fracturing process over an extended zone in silicon, which is controlled by the competition between the shock pressure load and the laser ablation rate. The qualities of the laser microstructuring and micromachining results are greatly improved by using an acoustic impedance matching approach.

• OSTI ID: 20709665
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 10 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABLATION
BRITTLENESS
FRACTURING
IMPEDANCE
LASER BEAM MACHINING
LASERS
MONOCRYSTALS
PRESSURE RANGE GIGA PA
PULSES
SILICON
SPALLATION
STRAIN RATE
THICKNESS
THRESHOLD ENERGY