A micromachined device made of semiconductor material is formed by: a semiconductor
body; an intermediate layer set on top of the semiconductor body; and a substrate,
set on top of the intermediate layer. A cavity extends in the intermediate layer
and is delimited laterally by bottom fixed regions, at the top by the substrate,
and at the bottom by the semiconductor body. The bottom fixed regions form fixed
electrodes, which extend in the intermediate layer towards the inside of the cavity.
An oscillating element is formed in the substrate above the cavity and is separated
from top fixed regions through trenches, which extend throughout the thickness
of the substrate. The oscillating element is formed by an oscillating platform
set above the cavity, and by mobile electrodes, which extend towards the top fixed
regions in a staggered way with respect to the fixed electrodes. The fixed electrodes
and mobile electrodes are thus comb-fingered in plan view but formed on different levels.
