Structural and optical properties of plasma oxidized films on GaAs1-xPx

Surfaces of GaAs1-xPx, where x-ranged from zero to unity, were oxidized by means of an oxygen plasma producing transparent and electrically insulating oxide films. The oxide growth rate approached one micron per second and the base material could be masked from oxidation by aluminum films. Electron beam diffraction analysis indicate that the films are polycrystalline and complex consisting of β - Ga2O3, and GaAsO4or GaPO4. Initially β - Ga2O3formed while GaAsO4or GaPO4appear in the latter growth stages. The index of refraction of the films measured at λ = 5461 Å was found to depend upon both the film thickness and the composition of the substrate material. Step etching techniques indicate the index of refraction increases gradually with distance from the surface to the bulk of the oxide.