Low-pressure etching of GaAs with multipolar plasma confinement

Anisotropic etching of GaAs with 100–400 eV ion radiation energies is reported in a low-pressure, magnetically confined multipolar plasma. Etch rates ∼0.5 μm/min and excellent surface texture are obtained in SiCl4, CFCl3, and CF2Cl2 at pressures of 0.5–2.0 mTorr. Schottky barrier measurements show low substrate damage for ion energies ≤200 eV, increasing sharply for higher energies. Survey spectra using x-ray photoelectron spectroscopy show that chlorine surface contamination also increases with ion radiation energy.