Time-resolved micro-Raman thermometry for microsystems

Micro-Raman thermometry has demonstrated to be a feasible technique for obtaining micron-scale spatial resolution of microelectronic and micro-electromechanical system (MEMS) temperatures. However, the low intensities of the Raman signals emerging from the device under study force the need for prolonged data collection times in order to obtain reliable temperature information. This characteristic currently limits Raman thermometry to steady state conditions, and thereby prevents temperature measurements of transient and fast time-scale events. In this paper we discuss the extension of the micro-Raman thermometry diagnostic technique to obtain transient temperature measurements on micro-electromechanical devices with 100 μs temporal resolution. Through the use of a phase-locked technique we are able to obtain temperature measurements on electrically-powered MEMS actuators powered with a periodic signal. Furthermore, we demonstrate a way of obtaining reliable micro-scale temperature measurements on devices that undergo mechanical movement during the device operation.