Materials Center Leoben Forschung GmbH, Roseggerstrasse 12, 8700 Leoben, Austria.
ams AG, Tobelbader Strasse 30, 8141 Premstaetten, Austria.
Sensors (Basel). 2019 Feb 7;19(3):672. doi: 10.3390/s19030672.
Metal oxide gas sensors generally need to be operated at elevated temperatures, up to and above 400 °C. Following the need for miniaturization of gas sensors and implementation into smart devices such as smartphones or wireless sensor nodes, recently complementary metal-oxide-semiconductor (CMOS) process-based micro electromechanical system (MEMS) platforms (micro-hotplates, µhps) have been developed to provide Joule heating of metal oxide sensing structures on the microscale. Heating precision and possible spatial temperature distributions over the µhp are key issues potentially affecting the performance of the overall gas sensor device. In this work, we use Raman spectroscopy to directly (in-situ and in-operando) measure the temperature of CMOS-based µhps during the application of electric current for Joule heating. By monitoring the position of the Raman mode of silicon and applying the theoretical framework of anharmonic phonon softening, we demonstrate that state-of-the-art µhps are able to reach the set temperature with an error below 10%, albeit with significant spatial temperature variations on the hotplate. This work demonstrates the potential of Raman spectroscopy for in-situ and in-operando temperature measurements on Si-based devices, an aspect of high relevance for micro- and nano-electronic device producers, opening new possibilities in process and device control.
金属氧化物气体传感器通常需要在高温下运行，高达 400°C 甚至更高。为了满足气体传感器的小型化以及集成到智能手机或无线传感器节点等智能设备中的需求，最近已经开发出基于互补金属氧化物半导体（CMOS）工艺的微机电系统（MEMS）平台（微热板，µhps），以提供金属氧化物传感结构在微尺度上的焦耳加热。加热精度和µhp 上可能的空间温度分布是可能影响整个气体传感器设备性能的关键问题。在这项工作中，我们使用拉曼光谱技术直接（原位和在位）测量在电流应用于焦耳加热时基于 CMOS 的µhps 的温度。通过监测硅的拉曼模式的位置并应用非谐声子软化的理论框架，我们证明了最先进的µhps 能够达到设定温度，误差低于 10%，尽管在热板上存在显著的空间温度变化。这项工作展示了拉曼光谱技术在 Si 基器件的原位和在位温度测量方面的潜力，这对于微纳电子器件制造商来说是一个非常重要的方面，为工艺和器件控制开辟了新的可能性。
