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A new room temperature wet chemical digital etching technique for GaAs is presented which uses hydrogen peroxide and an acid in a two‐step etching process to remove GaAs in approximately 15 Å increments. In the first step, GaAs is oxidized by 30% hydrogen peroxide to form an oxide layer that is diffusion limited to a thickness of 14 to 17 Å for time periods from 15 to 120 s. The second step removes this oxide layer with an acid that does not attack unoxidized GaAs. These steps are repeated in succession until the desired etch depth is obtained. Experimental results are presented for this digital etching technique demonstrating the etch rate and process invariability with respect to hydrogen peroxide and acid exposure times.

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New constant drain-current deep level optical/transient spectroscopy (CI D -DLTS/DLOS) methods to quantify trap energies and concentrations in AlGaN/GaN high electron mobility transistors (HEMTs) are described. These methods are applied to RF stressed HEMTs to characterize the impact of stressing on traps and identified a significant increase in virtual gate related levels.

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