Heating and photoionization of silicon structures at laser treatments

摘要

The processes of light absorption, generation of electron-hole pairs and thermal heating of thin-film silicon structures under the action of high-power nanosecond laser pulses are considered. The computer simulation of heating and photoexcitation of the implanted Si is carried out. The simulation results are compared with the experimental data on optical probing. The density of the generated electron-hole pairs and the temperature dependence of the light absorption by Si for the laser radiation with λ = 1.06 μm are estimated. These data can be used to control the depth distribution of the absorbed energy of the laser radiation. The laser modification of thin-film materials on Si by the temperature-controlled Si transparency is carried out when treating structures by the radiation directed from backside of the crystalline Si substrate. This method allows one to increase the uniformity of the laser radiation along its cross-section, to reduce the surface overheating degree and to avoid the surface disruption.