Laser Induced Breakdown Spectroscopy for Microanalysis of Surfaces

  • Author / Creator
    Banerjee, Shyama P
  • The utilization of Laser Induced Breakdown Spectroscopy (LIBS) as a potential material characterization technique has been demonstrated through academic and industrial research in past. LIBS has been applied for lateral surface scanning of materials and in depth resolution analysis. The necessity of improving lateral and depth resolution has led to the the development of microLIBS, a regime using low energy microjoule laser pulses. Femtosecond lasers have advanced the technique by its ability to produce high finer micromachined features. The optimization of pulse energy, optics, detectors and experimental environments are required to obtain precise surface microanalysis using LIBS. This thesis has been focused on a number of essential aspects of LIBS microanalysis. Laser ablation characteristics of materials depend on laser parameters and material properties. The single shot ablation threshold of chromium has been determined using UV femtosecond laser pulses and compared with two temperature model (TTM) predictions. The spatio-temporal evolution of the femtosecond laser induced micro-plasma plumes were characterized in the nanojoule ablation regime. The plume splitting, angular distribution of the plumes, plume lengths and plume images at threshold energies were characterized. Analytical models were used to compare plasma plume expansion and propagation characteristics. A LIBS depth profiling technique has been studied together with deep blind hole drilling using femtosecond laser pulses. The material removal rates were measured and compared with analytical calculations. The depth sensitive region that contributes to the LIBS emission has been evaluated for a single shot depth profiling study. It has been demonstrated by experiment and TTM model calculations that the depth sensitive region is much smaller than the ablated crater depth. Thin chromium lines on silicon wafers were prepared and scanning microanalysis across these metal strips using UV femtosecond pulses were carried out. Lateral resolution of the order of a micron has been obtained using LIBS.

  • Subjects / Keywords
  • Graduation date
    Fall 2014
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.