In-Situ Selective Area Etching of GaAs in Metalorganic Molecular Beam Epitaxy Chamber using Trisdimethylaminoarsenic

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Abstract
Selective area etching of GaAs using the metalorganic precursor, trisdimethylaminoarsenic (TDMAAs), is investigated under various etching conditions. The (100)-GaAs surface is partly masked using stripe shaped SiO2 films along the [011] and [0*BAR*1*BAR*1] directions. Cross-sectional scanning electron microscopy (SEM) observation shows that the etched shapes depend on both the stripe mask orientation and the substrate temperature, while they are almost independent of the TDMAAs flow rate and the stripe window width. Excellent mirror surface morphology is achieved at substrate temperatures below 500° C and high TDMAAs flow rates. It is possible to control the etched profiles by choosing etching conditions. TDMAAs is not only a promising arsenic source for growth but is also a quite useful in-situ etching gas source in metalorganic molecular beam epitaxy (MOMBE).