Etching in wide-bandgap semiconductors such as GaN aids applications including transistors, sensors, and radioisotope batteries. Plasma-based etching can induce surface damage and contamination that is detrimental to device performance. We present a photoelectrochemical approach to etching n-type GaN that is low-cost, simple, and environmentally benign compared to plasma approaches, with the potential for highly anisotropic etching that avoids material damage. n-GaN was etched in a dilute KOH solution with K2S2O8 oxidizer, ultraviolet (UV) irradiation, and a catalytic metal mask which served as both photomask and counter electrode. Relatively smooth, highly anisotropic, non-defect-selective etching was achieved at rates in excess of 200 nm/min when etching at 65°C. The obstacle of bath acidification was circumvented using the addition of buffering salts to the etchant bath, substantially extending the etchant bath lifetime and etching depth achievable in a single, uninterrupted etch. These results represent a major step toward a scalable, device-ready electrochemical etch for vertical GaN structures and devices.
CITATION STYLE
Dryden, D. M., Nikolic, R. J., & Islam, M. S. (2019). Photogalvanic Etching of n-GaN for Three-Dimensional Electronics. Journal of Electronic Materials. https://doi.org/10.1007/s11664-019-06982-5
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