New lithium gas sorbents: IV. Application to MEMS devices

A theory of gas sorption by lithium solid solutions, which is based on a simple diffusion model, has been applied to the processes of gettering residual gases in small sealed-off chambers of a MEMS-cavity type. The analysis of kinetics of the process leads to the conclusion that under certain conditions, which are formulated in the form of a criterial inequality G > 1, there is no further need of outside means for pumping down the microchambers before sealing-off. A vacuum inside the microchamber is created and further maintained for a long time at a constant level due to gas sorption by the getter material itself. The huge sorption capacity of lithium solid solutions is able to increase the lifetime of evacuated MEMS devices by more than one order of magnitude and to extend it to 20 years.