SQUARE-SHAPED TEMPERATURE DISTRIBUTION INDUCED BY A GAUSSIAN-SHAPED LASER-BEAM

A method is proposed to generate a square-shaped temperature distribution in substrates from a Gaussian-shaped laser source by transferring the Gaussian distribution of the laser beam into four one-quarter Gaussian-distributed beams. A mathematical model was derived to calculate the temperature rise induced by both the one-quarter Gaussian beam and four one-quarter Gaussian beams. The model was then applied to a silicon substrate. It is revealed that square-shaped temperature distributions can be obtained by this method if the distance between the peaks of the four one-quarter beams is arranged to be the same as the spot size of the original Gaussian beam. It is also found that the square shape of the temperature profile is almost of the same size as the original Gaussian beam and does not depend on the incident laser power (or the absolute temperature rise) and the substrate material.