US Patent 7545012 Capacitive micromachined ultrasound transducer fabricated with epitaxial silicon membrane

A capacitive micromachined ultrasound transducer (cMUT) cell is presented. The cMUT cell includes a lower electrode. Furthermore, the cMUT cell includes a diaphragm disposed adjacent to the lower electrode such that a gap having a first gap width is formed between the diaphragm and the lower electrode, wherein the diaphragm comprises one of a first epitaxial layer or a first polysilicon layer. In addition, a stress reducing material is disposed in the first epitaxial layer.