Impact of surface roughness on the stability of nanoelectromechanical pressure sensors in the Casimir regime

The stability of nanoelectromechanical pressure sensors working in the Casimir regime is considered with account of surface roughness on both the sensor membrane and the ground plate. The equilibrium positions of the sensor membrane are found from the balance between the external measured, elastic, electric pressures, and the Casimir pressure computed by means of the Lifshitz theory. It is shown that the stable equilibrium position of the sensor membrane is nearly independent of the surface roughness, whereas its unstable equilibrium position is shifted to larger membrane-plate separations. The use of these results for creating pressure sensors with further shrunk dimensions is discussed.