Multi-sensitive temperature sensor platforms using aluminum nitride MEMS resonators

Abstract

This paper presents three MEMS platforms that exhibit multiple thermal sensitivities and multi-frequency capabilities. Multiple sensors with a variety of operating frequencies and thermal sensitivities can co-exist in the same device wafer. Aluminum nitride is the active layer of the three platforms. The impact of stack and substrate modifications on the performance of test devices is discussed as well. To test the platforms’ performance, temperature sensors are realized using Lamb-acoustic-wave micro-electro-mechanical (MEMS) resonators, each one featuring a different thermal coefficient of frequency that scales with frequency. Resonators designed for frequencies between 200 MHz to 1.5 GHz operate at their first symmetric mode (S0) and feature first-order TCFs in the range from −12 up to −30 ppm °C−1 depending on the frequency and design. Furthermore, TCFs of devices can be tailored to get smaller values through process variations. The platforms exhibit high electromechanical performance, with quality factors in excess of 1500 and maximum effective coupling coefficient of 6.43% for radio frequency (RF) applications above 1 GHz.

Multimode excitations for complex multifunctional logic device

“…state '1') of each output. Alternatively, the switching energy can be evaluated using 1 2 C ∆V 2 based on the average of the consumed energy for different input combinations. For the switching voltage of 30 V as shown in figures 7(a) and (b), the corresponding capac itance and the switching energy for output 1 are 12.854 fF and 11.01 pJ, respectively, and for output 2 are 11.72 fF and 5.31 pJ, respectively.…”

“…In recent years, researchers have explored microelectrome chanical systems (MEMS) resonators for different applications such as sensors [1][2][3][4], actuators [5][6][7], filters [8][9][10], switches [11][12][13], memory [14][15][16] and logic gates [17][18][19][20]. There has been significant interest in using MEMS resonators par ticularly as digital computing devices due to their run time reprogramability and low energy consumption especially in the off state.…”

PVDF Sensor Stimulated by Infrared Radiation for Temperature Monitoring in Microfluidic Devices

“…Recently, there has been a great deal of interest in the use of pyroelectric effect for making thermal measurements and detecting electromagnetic radiations [ 36 , 37 , 38 ]. Low-temperature differential measurements, such as the evaluation of specific heat require high sensitivity and minimum joule heating, are readily provided by the pyroelectric devices [ 39 , 40 ]. There are different ways to characterize a thermometer, especially in the initial evaluation phase, by developing a correlation between the physical properties of the transducer with variations in temperature or by the evaluation of a thermal property of the material itself [ 41 ].…”