Stress analysis in group III-Nitride mems using simulation and raman spectroscopy

Abstract

Group III-N like AlN used for sensor or electronic applications is typically grown on a silicon substrate. Due to the comparably high lattice mismatch, the resulting sputtered or epi-layers are mostly biaxially stressed, but out of plane stresses can appear also. Generating micro electro mechanical systems (MEMS) of such layers, leads to relaxation and thus to a complex stress distribution within the MEMS. This distribution is to be investigated for different MEMS structures using Raman spectroscopy. Additionally, FEM simulations shall be carried out for modeling the stress distribution numerically and the results compared to unstressed structures. The Euler-Bernoulli-Theory (EBT) is common analytical theory for the description for the vibrational behavior of MEMS, but lacks the possibility to consider complex stress in the structures. Hence, an error analysis is to be made regarding the impacts on using the EBT for real stressed structures.