Temperature compensated resonance modes of degenerately n-doped silicon MEMS resonators

We model the temperature coefficients of resonance modes of degenerately n-type doped silicon resonators. By combining results from FEM-based sensitivity analysis and modelling of elastic constants of silicon with free carrier theory we are able to identify classes of resonance modes that can be temperature compensated via n-type doping. These include bulk modes such as the width/length extensional modes of a beam, Lamé/square extensional modes of a plate resonator, as well as flexural and torsional resonance modes. Our results show that virtually all resonance modes of practical importance can reach zero TCF when the resonator is aligned to a correct crystallographic orientation and when the n-dopant concentration is suitably selected.