The wet oxidation kinetics of AlAs layers of interest in vertical cavity surface emitting laser (VCSEL) fabrication are investigated in detail. The process is modeled as a diffusion-reaction process. For oxidation over a long time interval, variation of the oxidation rate with the variation of the radius of the etched mesa of the VCSEL is observed. A theory has been developed to obtain the rate equation of the oxidation process and the dependence of the oxidation rate on the size of the VCSEL is explained.

The use of carbon nanotubes as tips in atomic force microscopy for a systematic study of dry etching pattern transfer in GaAs is described. The GaAs samples are patterned via electron beam lithography and then etched using magnetron reactive ion or chemically assisted ion beam processing. The technique allows diagnosis, in air, of etched features with scale sizes of Ͻ100 nm.

Magnetron enhanced reactive ion etching of SiC has been investigated in SF6 plasmas. Etch rate was determined as a function of cathode power density (0.1–0.5 W/cm2), pressure (1–5 mTorr), and flow rate (5–15 sccm). The highest SiC etch rates yet reported (450 nm/min) were achieved, at low cathode bias voltage (100 V). Anisotropic etch profiles were obtained with smooth etch surfaces free of micromasking. Addition of O2 to the SF6 feed gas did not increase the etch rate.

Magnetron reactive ion etching of GaN in BCl3 plasmas was investigated as a function of cathode power density, flow rate, and pressure. GaN etch rates were achieved (350 nm/min), which were twice the highest etch rate previously reported, and at low cathode bias voltages (<100 V). Auger electron spectroscopy measurements revealed the etched surfaces to be Ga deficient to a depth of 10 nm, with a surface chlorine residue of <1 at. %. Magnetron dry etching appears well suited to applications such as mesa definitions for photonic devices in the GaN materials system.

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