Thermogravimetric Analysis Above 200°C/Min Using Integrated Resonant Microcantilevers

We report on rapid thermogravimetric analysis (TGA) using MEMS resonant cantilevers at a heating rate exceeding 200°C/min (the limit of state-of-the-art furnace-based conventional TGA instruments). Each MEMS cantilever integrates resonance excitation/excitation resistors for mass sensing and a microheater for sample heating. By leveraging the miniature device size, and unique thermal isolation structure design, we achieve temperature-programmed heating in the sample loading region at a heating rate of up to 1000°C/min. We then perform rapid TGA measurements on calcium oxalate monohydrate (CaC
2
O
4
•H
2
O) using our TGA chips. We observe 3-stage chemical decomposition, and the weight loss values agree with the theoretical ones, at a heating rate up to 1000°C/min (5 times higher than those of conventional TGA). We also evaluate the thermal lag using termination temperature and estimate a linear coefficient of 0.84°C/(°C/min) for conventional TGA and 0.076°C/(°C/min) for the cantilever-TGA, which is 11 times smaller. Our integrated resonant cantilevers can greatly accelerate the TGA characterization while maintaining good accuracy.