Assessment of the crystalline orientation of nanoscale semiconductor structures via atom probe tomography

We demonstrate the application of atom probe tomography for assessing the crystalline orientation of nanoscale semiconductor structures via the analysis of charge state ratio maps in the detector space. The experimental realization is carried out in the context of adventitious cone-shaped domains present in AlGaN quantum dot superlattices. The cone-shaped domains, which emerge from shallow pits generated in AlN and propagate through the superlattices, are shown to exhibit small misorientation angles of their crystalline 〈0001〉 poles. The results of the atom probe tomography analysis are confirmed by convergent beam electron diffraction measurements. The use of this methodology adds another layer to the application of this technique to semiconductor nanoscale systems, providing not only compositional maps but also information on the crystallographic orientation.