Pressure transducer with composite diaphragm

摘要

A method of forming a composite diaphragm for a pressure transducer is disclosed. The method comprises providing a substrate layer having a first conductivity type and a first surface. Positive implants are deposited in the first surface of the substrate layer, and an epitaxial layer is grown on the first surface of the substrate layer so that the positive implants form positive diffusions in the epitaxial layer. An oxide pattern is formed on the epitaxial layer, and a top layer is deposited over the epitaxial layer and oxide pattern. The substrate layer and positive diffusions of the epitaxial layer are then etched to form the composite diaphragm. The positive diffusions can be patterned so that the resulting etched structure has improved diaphragm performance characteristics. For example, the remaining pattern can include a plurality of bosses and interconnecting battens so that the diaphragm has a relatively high burst pressure and a high output signal with improved linearity at low pressures.