Scaling laws of subpicosecond laser-induced breakdown in dielectric films (Poster Award Paper)

Abstract

The scaling of the laser fluence for dielectric breakdown with respect to pulse duration and material bandgap was investigated in the sub-ps regime using various oxide films (TiO 2 , Ta 2 O 5 , HfO 2 , Al 2 O 3 , and SiO 2 ). A phenomenological model attributes the pulse duration dependence to the interplay of multiphoton ionization, impact ionization, and sub-ps electron decay out of the conduction band. The observed linear scaling of the breakdown fluence with bandgap, which is nearly independent of the pulse duration, can be explained within the framework of our model by invoking the bandgap dependence of the multi-photon absorption coefficient from Keldysh photoionization theory.