Influence of aluminum nitride crystal orientation on MEMS energy harvesting device performance

Abstract

Aluminum nitride (AlN) is a widely researched piezoelectric material due to its CMOS compatibility. One of the most common applications for AlN is in the area of vibrational energy harvesting. The piezoelectric quality of AlN is related to the crystal orientation of the film and optimal conditions are obtained when AlN is c-axis aligned with a (0 0 2) orientation. AlN can be a challenging material to integrate into a fabrication process due to orientation dependency of the fabrication process. This paper reports on the effects of non-(0 0 2) oriented AlN peaks on an energy harvesting MEMS cantilever structure. Results show that FWHM values of the AlN films from different wafers were approximately the same 8.5°, 8.7°, and 9°, however wafer 1 had additional peaks at (1 0 2) and (1 0 3), which significantly affected the piezoelectric constants and the amount of power generated. The measured d31 value for the wafers were 2.04, 1.97, and 0.84 pm V−1, and the power generated was 0.67, 0.64, and 0.24 µW respectively. These values show that non-peaks of AlN can cause a significant decrease in the piezoelectric constant, which causes significant decrease in the ability to generate power from an AlN film.

Effects of in-situ poling and process parameters on fused filament fabrication printed PVDF sheet mechanical and electrical properties

“…Unlike other common piezoelectric materials, PVDF does not require high processing temperatures [17] when compared to electroceramics like PZT (~600°C+) and can be extruded instead of sputtered like aluminum nitride [18]. The processing melt temperature for PVDF is on par with current open source FFF processes 170-200°C [19].…”

Acoustic Energy Harvesting Through Multilayer Piezoelectric Harvester Model

“…In table 1, first column shows the different methodologies, second column presents the power; third column represents the power density, fourth normalised Power Density and Volume. Here in terms of power paper [18] observes the 0.68 , [19] observes 0.63 , [20] observes 1.46, [21] observes 0.80 and existing mechanism [22] observes 1.03 whereas proposed protocol observes the 1.4. Similarly, in terms of power density the value observed by these methods as [18], [19], [20], [21] and existing [22]are 5.66, 0.46, 1.14, 2.35, 9.36 whereas our methodology observes the 9.61.…”

Preparation of (001) preferentially oriented titanium thin films by ion-beam sputtering deposition on thermal silicon dioxide

“…The advantages of titanium thin films are good electric conductivity, extraordinary chemical resistivity, thermal stability, high hardness, high melting point, and lower number of crystallographic imperfections [1][2][3][4][5]. Crystallographic orientation of titanium thin films has to be controlled during the deposition process to obtain specific properties (e.g., mechanical, chemical) suitable for an eventually required application [6,7]. Some of recent MEMS devices use the piezoelectric effect for energy harvesting or sensing purposes [8].…”