Integration of structurally-stable isolated capacitive micromachined ultrasonic transducer (CMUT) array cells and array elements

US8563345B2 · kind B2 · utility

Assignee

• NATIONAL SEMICONDUCTOR CORPORATION · US

Inventors

• Steven J. Adler · Cape Elizabeth, US
• Peter Johnson · Sunnyvale, US
• Gokhan Percin · Los Gatos, US
• Shahram Mostafazadeh · Santa Clara, US

Key dates

• Filing date: Mar 13, 2012
• Grant date: Oct 22, 2013
• Expiry date: Mar 13, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/76898
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for forming a capacitive micromachined ultrasonic transducer (CMUT) includes forming multiple CMUT elements in a first semiconductor-on-insulator (SOI) structure. Each CMUT element includes multiple CMUT cells. The first SOI structure includes a first handle wafer, a first buried layer, and a first active layer. The method also includes forming a membrane over the CMUT elements and forming electrical contacts through the first handle wafer and the first buried layer. The electrical contacts are in electrical connection with the CMUT elements. The membrane could be formed by bonding a second SOI structure to the first SOI structure, where the second SOI structure includes a second handle wafer, a second buried layer, and a second active layer. The second handle wafer and the second buried layer can be removed, and the membrane includes the second active layer.