Design, processing and testing of a MEMS energy grooming structure for initiator materials

A common problem experienced by micro-electro-mechanical system (MEMS) initiators is unintentional triggering in a transient high-pulse environment owing to low ignition energy. Herein, therefore, combining the size effect of the Paschen's law with a modified semi-empirical formula of the secondary electron emission coefficient, a theoretical calculation was carried out to improve the electrostatic grooming structures. It was found that the size effect of the Paschen's law is owing to the distance-dependent process dominance of the Thomson discharge process and the field-induced electron emission process. A microscale breakdown model was, thus, proposed based on field-induced electron emission and the secondary electron emission coefficient. The structural simulations and the optimization of various materials were carried out using the multiphysics field simulation software (i.e., COMSOL), and an electrostatic grooming device was subsequently fabricated. During experimental testing, the transient voltage of an electrostatic grooming device with a 1μm-wide comb gap could be groomed over 130 V. Furthermore, the model was in good agreement with the experimental results in the range of less than 2μm and more than 9 μm. In the optimum range of 2-9μm, the result of the test differed from the model by less than 15%. The model, therefore, possesses excellent adaptability in this scale range and can be used to greatly improve the antistatic characteristics of initiators.