In situ etching of \b{eta}-Ga2O3 using tert-butyl chloride in an MOCVD system

Cameron A. Gorsak; Henry J. Bowman; Katie R. Gann; Joshua T. Buontempo; Kathleen T. Smith; Pushpanshu Tripathi; Jacob Steele; Debdeep Jena; Darrell G. Schlom; Huili Grace Xing; Michael O. Thompson; Hari P. Nair

arXiv · 2408.01574

In situ etching of \b{eta}-Ga2O3 using tert-butyl chloride in an MOCVD system

Cameron A. Gorsak·Henry J. Bowman·Katie R. Gann·Joshua T. Buontempo·Kathleen T. Smith·Pushpanshu Tripathi·Jacob Steele·Debdeep Jena·Darrell G. Schlom·Huili Grace Xing·Michael O. Thompson·Hari P. Nair

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Abstract

In this study, we investigate in situ etching of \b{eta}-Ga2O3 in a metal-organic chemical vapor deposition (MOCVD) system using tert-Butyl chloride (TBCl). We report the successful etching of both heteroepitaxial (-201)-oriented and homoepitaxial (010)-oriented \b{eta}-Ga2O3 films over a wide range of substrate temperature, TBCl molar flows, and reactor pressures. We identify that the likely etchant is HCl (g) formed by the pyrolysis of TBCl in the hydrodynamic boundary layer above the substrate. The temperature dependence of the etch rate reveals two distinct regimes characterized by markedly different apparent activation energies. The extracted apparent activation energies suggest that at temperatures below ~800 {\deg}C the etch rate is likely limited by desorption of etch products. The relative etch rates of heteroepitaxial (-201) and homoepitaxial (010) \b{eta}-Ga2O3 were observed to scale by the ratio of the surface energies indicating an anisotropic etch. For (010) homoepitaxial films, relatively smooth post-etch surface morphology was achieved by tuning the etching parameters.

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Cameron A. Gorsak, Henry J. Bowman, Katie R. Gann, Joshua T. Buontempo, Kathleen T. Smith, Pushpanshu Tripathi, Jacob Steele, Debdeep Jena, Darrell G. Schlom, Huili Grace Xing, Michael O. Thompson, Hari P. Nair. 2024-08-02. In situ etching of \b{eta}-Ga2O3 using tert-butyl chloride in an MOCVD system. https://arxiv.org/abs/2408.01574

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