Dry Etching of GaAs , AlGaAs , and GaSb in Hydrochlorofluorocarbon Mixtures

Abstract

Reactive ion etching (RIE) of , , and in the hydrochlorofluorocarbons and has been investigated as a function of etch time, discharge power density, pressure, and additive gas ( or ). There is no incubation time required for the commencement of etching, and the etch rates are in the range 200 Å · min−1 (for ) to 1000 Å · min−1 (for ) for moderate power densities (0.56 W · cm−2). The etched surfaces have smooth morphologies for all three materials, and there is no significant lattice disorder introduced into , as detected by photoluminescence and diode current‐voltage measurements, provided the discharge power densities are kept below ∼0.7 W · cm−2. Hydrogen passivation of the Si dopants in n‐type is detected for both gases, but is more prevalent with . Thin (≤ 40Å) surface residue layers of Cl [comprising 5–9 atom percent (a/o)] and F (0.9–3 a/o) for and , and 23 a/o for ) are found on all samples after RIE, but these can be removed by simple solvent cleaning.