TRIPLE-CRYSTAL X-RAY-DIFFRACTION ANALYSIS OF REACTIVE ION ETCHED GALLIUM-ARSENIDE

The effect of BCl3 reactive ion etching on the structural perfection of GaAs has been studied with diffuse x-ray scattering measurements conducted by high-resolution triple-crystal x-ray diffraction. While using a symmetric 004 diffraction geometry revealed no discernible differences between etched and unetched samples, using the more surface-sensitive and highly asymmetric 113 reflection revealed that the reactive ion etched samples-etched displayed less diffusely scattered intensity than unetched samples, indicating a higher level of structural perfection. Increasing the reaction ion etch bias voltage was found to result in decreased diffuse scattering initially, until an apparent threshold voltage was reached, after which no further structural improvement was observed. Furthermore, we have shown that this reduction in process-induced surface structural damage is not due merely to the removal of residual chemical-mechanical polishing damage.