Laser-Ablation of Various Oxide Materials Over Large Areas

Abstract

Laser-Ablation (LA) had received little attention prior to the first published report of depositing Y1Ba2Cu3O7-x) (YBCO) thin films with this novel method.[1] However, LA has been used to produce films of infrared materials for some time[2], and the recent discovery of 1-igh Temperature Superconductors (HITS) has sparked considerable interest in this relatively obscure Physical Vapor Deposition (PVD) technique. Over the past three years, a variety of in-situ LA processes for producing films of HTS compounds, as well as other materials, have been reported in the literature.[3,4,5,6,7] Like any other PVD technique, LA has its own unique advantages anid disadvantages. The main advantages of LA include: 1) its ability to accurately replicate the stoichiometry of the ablation target within the laser-deposited film; 2) the high energy of the ablated species which may enhance the quality of film growth; 3) it does not require hot filaments which allow a number of reactive gases to be present in the chamber during deposition; and 4) a wide array of complex chemical compounds can be deposited. Two of the main problems facing this emerging PVD technique have been: 1) it has been applied mostly to small area deposition (<6 cm2) with poor uniformity, and 2) the ablated films typically display a large number- of particles ranging in size from 0.5 μm to over 10 μm, whose presence may significantly hamper a number of microelectronic device applications.