A MEMS device and method, comprising: a substrate; a beam; and a cavity located therebetween; the beam comprising a first beam layer and a second beam layer, the first beam layer being directly adjacent to the cavity, the second beam layer being directly adjacent to the first beam layer; the first beam layer comprising a metal or a metal alloy containing silicon; and the second beam layer comprising a metal or a metal alloy substantially not containing silicon. Preferably the second beam layer is thicker than the first beam layer e.g. at least five times thicker, and the first beam layer comprises a metal or alloy containing between 1% and 2% of silicon. The second beam layer provides desired mechanical and/or optical properties while the first beam layer prevents spiking.