Raman spectroscopic calibrations of phonon deformation potentials in wurtzitic AlN

Abstract

A controlled biaxial stress field generated in a ball-on-ring configuration was applied on a thin hexagonal (0001)AlN film grown on (001)Si substrate, and the phonon deformation potential (PDP) constants of the A1 (TO), E2 (high), and A1 (LO) Raman modes were retrieved from the respective spectral shifts. Measurements were done: (i) at given fixed locations upon increasing the externally applied load; and (ii) along spectral line scans performed at a fixed load. The reliability of the retrieved PDP values, in comparison with values previously reported in the literature, was examined by a further evaluation of the residual stress field stored in the AlN/Si system associated with the tip of a crack propagated from the corner of a pyramidal indentation. The PDP assessments were confirmed to be reliable owing to a close correspondence among stress intensity factors independently retrieved from different Raman bands.