The results of this paper are pertinent to micromachined integrated chemical sensors, infrared sources and hotplates, among others. We report on the operation and characterization of micromachined complementary metal-oxide semiconductor (CMOS) microstructures with integrated CMOS polysilicon heaters at temperatures up to 1200 K. The new results concern the stability of integrated CMOS polysilicon heaters under such extreme conditions. Two resistance drift phenomena appearing above the polysilicon recrystallization temperature T cr ≈ 870 K were identified. The first is a reversible resistance relaxation leading to resistance changes of several tens of per cent. Relaxation times are of the order of minutes and point to a thermally activated process. The second drift mechanism leads to slow resistance changes, for example, 3% after six hours above T cr . Temperature calibration of such devices supported by finite element simulations is proven to be feasible and reliable. Despite the large temperature gradients in the heated microstructures, natural convection in the surrounding gas was found to be ineffective in comparison with heat conduction.
Ti-Ni-Cu shape memory thin films within a broad composition range were investigated by the cantilever deflection method using combinatorial methods. Optimal compositions with improved functional properties, i.e. large recovery stress, high transformation temperatures, low thermal hysteresis width and small temperature interval of transformation, were identified using a newly defined figure of merit. Of the investigated alloys, Ti 50 Ni 41 Cu 9 and Ti 45 Ni 46 Cu 9 exhibit the best shape memory properties for compositions showing a B2 → B19 and a B2 → R-phase transformation, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.