Dear Mr Ma Bin, Check out the articles written by Pontus Eriksson and Göran Stemme between '94 and '96. They made bolometers using tSi3N4 on polyimide. Search in JMEMS and Sensors and Materials. Wouter van der Wijngaart Kungl. Tekniska Högskolan Tel: +46 - (0)8 - 790 66 13 S3, Elektrisk mätteknik Fax: +46 - (0)8 - 10 08 58 100 44 Stockholm Minicall: +46 - (0)740 - 26 71 28 Sweden e-mail: wouter@s3.kth.se http://www.s3.kth.se/instrlab/staff/wouterw.html