GaAs Radiation Damage Induced by Electron Cyclotron Resonance Plasma Etching with SF₆/CHF₃

After SF 6 /CHF 3 plasma exposure, the sheet resistance of Si-doped GaAs layers is higher because of carrier reduction near the surface and sputter etched surface, and this electrical and physical damage is found to depend on rf-power and µ-wave power. The carrier reduction can be almost restored by annealing at 450° C for 30 min. Exposures to He plasma or CHF 3 plasma cause more extreme carrier reduction than does exposure to SF 6 plasma, indicating that the carrier reduction in the damaged layers is predominantly due to the bombardment by low-mass fragments such as H and He. Low-temperature (4.2 K) photoluminescence of SF 6 /CHF 3 -plasma-exposed GaAs shows a broad and complicated spectrum (ranging from 1.25 to 1.43 eV) related to defect-complex by incorporation of hydrogen.