Effects of plasma treatment on evolution of surface step-terrace structure of critically cleaned c-plane sapphire substrates: An AFM study

- Evolution of step-terrace structure of c-plane sapphire substrates irradiated with low-pressure air plasma was studied with AFM.
- Ten minutes irradiation causes pairing of neighboring terraces into alternating wider and narrower terraces.
- Steps roughening and terrace etching occur after 20 min irradiation.
- Thirty minutes irradiation creates “step-terrace free” morphology with etched pits which are stable against annealing.