Oxidation of silicon surfaces by CO2 lasers

We report for the first time, the use of a focussed CO2 laser beam and a controlled oxygen atmosphere to induce localized oxidation on the surface of a silicon wafer. These thin oxide films have been compared by infrared spectrometry with thin furnace-grown layers. We conclude that the laser-grown oxides are compositionally similar to conventional layers, and can be described by the formula SiO2. In contrast the half-width of the Si-O stretching vibration at 1070 cm−1 was found to be consistently less than for furnace-grown oxides. By fabricating simple Al-SiO2-Si-Al diodes, the dielectric properties of the films have been studied.