A silicon micromachined infrared emitter based on SOI waf

Abstract

An improved fabrication technique for silicon-based MEMS (MEMS: microelectromechanical systems) Infrared (IR) emitter is presented. The IR emitter was fabricated on silicon-on-insulator (SOI) wafer. The resistively heated polysilicon membrane fabricated by using deep reactive ion etching (DRIE) process on backside of SOI wafer has a low thermal mass structure, thus this IR-emitter can be modulated at high frequency. Additionally, the usage of the DRIE process instead of the wet etching process provides a more optimum design for the chip dimension. An appropriate boron (B) dope was used to realize the infrared absorption of silicon or infrared transparence of silicon for achieving self-heating or body emitting effect. By using the SOI wafer, the fabrication processes are simplified, and the production costs are decreased. The membrane temperature and emission spectrum of IR emitter were measured with thermal imaging system and spectroradiometer. The experimental results show that the IR emitter exhibits a strong emission in middle infrared range, and the modulation frequency can reach to 45Hz at 50% modulation depth. It is expected that this IR-emitter can be used in low cost sensing system.