The fabrication of capacitive pressure sensors, using silicon integrated circuit processes is described. Polysilicon diaphragms are laid down using the conventional LPCVD technique. A cavity between the polysilicon layer and silicon substrate is created by etching away an intermediate oxide layer. The subsequently sealed cavity with deformable polysilicon membrane decreases in volume with a positive differential pressure between outside and inside. Capacitance changes between an electrode on the membrane and the silicon substrate allow pressure changes to be measured. The batch fabrication technology for microminiature device manufacture is described and electrical characteristics of the devices presented.