2003/06/12 by B. Jogai, J. D. Albrecht, E. Pan
Engineering · Physics and Astronomy · #Acoustic Wave Resonator Technologies #Advanced Sensor and Energy Harvesting Materials #GaN-based semiconductor devices and materials #cond-mat
paper · pdf · doi:10.1063/1.1620378
published as Journal of Applied Physics 94, 6566 (2003) · revtex
arxiv created 2003/06/12 · openalex publication_date 2003/11/07 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The strain and electric fields present in free-standing AlGaN/GaN slabs are examined theoretically within the framework of fully coupled continuum elastic and dielectric models. Simultaneous solutions for the electric field and strain components are obtained by minimizing the electric enthalpy. We apply constraints appropriate to pseudomorphic semiconductor epitaxial layers and obtain closed-form analytic expressions that take into account the wurtzite crystal anisotropy. It is shown that in the absence of free charges, the calculated strain and electric fields are substantially different from those obtained using the standard model without electromechanical coupling. It is also shown, however, that when a two-dimensional electron gas is present at the AlGaN/GaN interface, a condition that is the basis for heterojunction field-effect transistors, the electromechanical coupling is screened and the decoupled model is once again a good approximation. Specific cases of these calculations corresponding to transistor and superlattice structures are discussed.