X-ray diffraction studies of GaN p-i-n structures for high power electronics

Abstract

We have investigated the influence of the ambient exposure and/or ICP etching on the structure and properties of GaN p-i-n structures for high power electronics. To quantify the concentration of various native and extrinsic point defects, we utilize a combination of ion beam analyses in conjunction with x-ray diffraction. The full width at half max (FWHM) of phi and omega scans were used to quantify the mosaicity and threading dislocation (TD) densities at the p-i interfaces. The lowest densities of c-type and highest densities a-type TD components are observed for the “in-situ” GaN structure, which also produces the highest interfacial donor-acceptor pair (DAP) cathodoluminescence (CL) emissions. Interestingly, elastic recoil detection analysis (ERDA) and Rutherford backscattering spectroscopy reveal the lowest interfacial [H] but the highest fraction of displaced Ga atoms, suggesting efficient incorporation of MgGa in the in-situ structure. On the other hand, for the ex-situ structures, minimal interfacial [H] is also observed, but the lowest interfacial NBE and DAP CL emission is apparent as well as the highest density of c-type TD components. The relationship between interfacial [H], displaced Ga, CL emission features, and c- and a-type dislocation densities will be discussed.