The features of thin-film membranes, which are formed above round holes in silicon substrates using the Bosch-process are considered. The membrane has a complex shape due to the presence of the stress state of the initial films. The analysis of the dependence of the membrane deflection w on the supplied overpressure P is used to calculate the mechanical characteristics of the membranes. In this case, it is necessary to determine directly on the membrane its diameter, the thickness of the constituent layers, the change in the topography of the membrane surface over its entire area as the overpressure increases. Determination of the membrane diameter and the thicknesses of the constituent layers is shown by the example of p-Si*/SiNx/SiO2 and SiNx/SiO2/SiNx/SiO2 membranes. We used spectral ellipsometry, energy-dispersive X-ray spectroscopy, optical profilometry, optical microscopy. The influence of the peculiarities of the fixing conditions on the stress-strain state of membranes is shown, and the assessment is carried out by means of numerical modeling. A technique has been developed for measuring and calculating the mechanical characteristics of membranes that have an initial deflection. The calculation result is shown on the example of a membrane with an initial deflection of 2 μm --- SiNx/SiO2/SiNx/SiO2 and a membrane with an initial deflection of 30 μm --- Al/SiO2/Al. Keywords: stress, bulging method, films, thin-layer coating, film thickness, membrane, pressure blister test, residual stress, microelectromechanical systems, MEMS, silicon substrate, large deformations, strain, deflections, circular membrane, bulge testing.
The reproducibility of complementary metal-oxide-semiconductor (CMOS) technology makes it very promising for creating commercially available vacuum emission micro/nanoelectronic devices. However, there are a number of challenges that occur with CMOS, including current hysteresis, transition to the generation of self-sustained plasma, and thermal melting of the cathode. These issues affect the process of field-electron emission and lead to instability and subsequent degradation of field-emission cathodes. More detailed study is needed in order to address these negative effects. In this study, an array of nanoscale silicon needle-type cathodes and a single blade-type cathode were placed in vacuum to characterize their field-emission properties. The hysteresis nature of the field-emission current and the smooth transition from field emission to the generation of self-sustained plasma in the interelectrode space were simultaneously observed. Based on these experimental results, the authors propose the possible origins and mechanisms underlying these two phenomena. It was theoretically found that at field-emission currents corresponding to the observed melting point of the silicon nanocathodes, the melting point of silicon is not reached, which indicates the need to take into account additional effects of field emission, such as sputtering of the anode material. The results are useful for developing field-emission nanodevices based on silicon CMOS technology.
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.