EXCIMER-LASER REMOVAL OF SIO2 PATTERNS FROM GAAS SUBSTRATES

SiO2 patterns on GaAs substrates can be completely removed by KrF excimer-laser irradiation in air. The substrate surface is found to be dean, without residual SiO2 patterns or other contaminants. Free-standing SiO2 microstripes can be formed by this method. This technique provides an efficient dry process to remove SiO2 patterns on GaAs substrates, instead of the wet etching process. The mechanisms to peel off the SiO2 patterns from the GaAs substrate are considered to involve direct momentum transfer, photodecomposition of the interface substance, and thermal expansion of the substrate.