Hi, all, Just wondering why people prefer using poly-si instead of other mat. such as metal for typical thermal lateral actuator? Johnny =========================================== Johnny H.HE, Ph.D. Candidate Division of Electrical Engineering, Engineering Department,Cambridge University,CB2 1PZ, UK or Downing College, Cambridge, CB2 1DQ ,UK Email: jh353@cam.ac.uk Tel:+44 1223 765199 Fax:+44 1223 332662 ===========================================