Extensive Studies of the Plume Deflection Angle During Laser Ablation of Si Target

Abstract

The plume deflection effect during long laser irradiation of a Si target has been extensively studied. Two different laser ablation experiments were performed to study the plume deflection angle and the ablation rate versus the number of laser pulses/site. Scanning electron microscopy (SEM) analyses and profilometry of the Si target surface were performed to examine the continuous morphological changes produced by the laser irradiation. The roughening of the target surface strongly influenced the formation and expansion of the Si plume. Plume deflection angles higher than 30° have been observed by a digital camera. Complementary mass spectrometer measurements confirmed that the ion flux distribution is strongly oriented along the laser beam direction. In addition to laser ablation experiments, two other laser deposition experiments were performed: with the conventional configuration and with a new approach, termed frontal off-axis deposition. The new pulsed-laser deposition configuration provides much better control of uniformity and film thickness than the conventional deposition configuration.