PULSED EXCIMER-LASER ETCHING OF LA0.75CA0.25MNOX THIN-FILMS

Pulsed (lambda=248 nm, pulse width=20 ns) KrF-excimer-laser-induced etching of La0.75Ca0.25MnOx (LCMO) thin films exhibiting giant magnetoresistance (GMR) has been studied. The variation of etch depth as a function of the number of laser pulses shows a linear dependence in the fluence range between 0.15 and 4 J cm(-2). The threshold fluence for ablation is found to be 0.07 J cm(-2). The photoetching process is seen to follow the Beer-Lambert's relation based on a linear absorption model with an absorption length of 28.3 nm. The nanomorphology of the laser etched surface as revealed by atomic force microscopy shows significant improvement in the surface smoothness of the deposited films for etching at low energy densities (typically 0.17 J cm(-2)) and enhanced roughness at higher energy densities (typically 0.86 J cm(-2)). Changes in the resistivity and GMR effect due to laser treatment are also examined. (C) 1995 American Institute of Physics.