In-Situ Formation of Quantum Size Features on III-V Heterostructures Using a Native Oxide Mask

We have used a native oxide layer present on the surface of III-V compounds as an etch mask for transferring small features onto the underlying heterostructure. The mask pattern is formed by locally removing an extremely thin native oxide (typically less than ten-angstroms on InP) with a focused Ga ion beam. This can be done with moderate ion dosed, ~5 x 10 sup 14 cm sup -2, at an energy of 20 keV. The mask pattern is then transferred into the substrate by dry etching in Cl sub 2 atmosphere at 200C with or without the assistance of a broad area Ar ion beam.