THE MECHANISM OF LASER ACTIVATION AND METALLIZATION OF AL2O3

This paper presents experimental results on the activation of Al2O3 fo r the chemical deposition of metals. Laser activation of a ceramic sur face consists of its ability to reduce a metal from solution and is ac companied by a change of its absorption spectrum consisting of the app earance of an absorption peak near 250 nm and simultaneously a quasi-c ontinuous absorption band extending from the UV to the IR region. The indicated spectral features are associated with the formation of F+ ce nters (250 nm) on the surface and a decrease of the Al2O3 band gap, ca used by the presence of residual mechanical stresses in the material. The dynamics of the appearance of stresses in the process of activatin g the ceramic by the radiation of an ArF excimer laser with a time res olution of 10 ns are investigated. The possibility of mechanical (nonl aser) activation of Al2O3 ceramic is demonstrated experimentally. A ne cessary condition for surface activation for the chemical deposition o f metals is the creation in the band gap of energy levels close to the reduction potential of a metal ion from solution. (C) 1996 The Optica l Society of America.