Micromachined thermoelectric sensors and arrays and process for producing

US6046398A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Marc C. Foote · La Cañada Flintridge, US
• Eric Jones · Los Angeles, US
• Thierry Caillat · Pasadena, US

Key dates

• Filing date: Nov 4, 1998
• Grant date: Apr 4, 2000
• Expiry date: Nov 4, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G01J5/12
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Linear arrays with up to 63 micromachined thermopile infrared detectors on silicon substrates have been constructed and tested. Each detector consists of a suspended silicon nitride membrane with 11 thermocouples of sputtered Bi--Te and Bi--Sb--Te thermoelectric elements films. At room temperature and under vacuum these detectors exhibit response times of 99 ms, zero frequency D* values of 1.4.times.10.sup.9 cmHz.sup.1/2 /W and responsivity values of 1100 V/W when viewing a 1000 K blackbody source. The only measured source of noise above 20 mHz is Johnson noise from the detector resistance. These results represent the best performance reported to date for an array of thermopile detectors. The arrays are well suited for uncooled dispersive point spectrometers. In another embodiment, also with Bi--Te and Bi--Sb--Te thermoelectric materials on micromachined silicon nitride membranes, detector arrays have been produced with D* values as high as 2.2.times.10.sup.9 cmHz.sup.1/2 /W for 83 ms response times.