• 
  Rudloff, D. ; Riemann, T. ; Christen, J.; Liu, Q.K.K.; Kaschner, A.; Hoffmann, A.; Thomsen, Ch.; Vogeler, K.; Diesselberg, M.; Einfeldt, S.; Hommel, D.: Stress analysis of Al_xGa_{1 x}N films with microcracks. Applied Physics Letters 82 (2003), p. 367-369

10.1063/1.1534408

Abstract:
Thick Al_(x)Ga_(1-x)N epilayer with microcracks grown by metalorganic vapor-phase epitaxy on a GaN buffer above a (0001) sapphire substrate was comprehensively characterized by spatially and spectrally resolved cathodoluminescence (CL) and micro-Raman spectroscopy. The variation of the CL line shift and the micro-Raman measurements between the cracks are consistent with the interpretation that AlGaN is to a large extent stressed like a two dimensiional film between the microcracks with nearly full relaxation close to the cracks. A satisfactory theoretical confirmation of the stress distribution was obtained by a three-dimensional finite-element application of the elasticity theory.