MEMS-Based Electrochemical Seismometer with a Sensing Unit Integrating Four Electrodes

Abstract

This paper presents a new process to fabricate a sensing unit of electrochemical seismometers using only one silicon–glass–silicon bonded wafer. By integrating four electrodes on one silicon–glass–silicon bonded wafer, the consistency of the developed sensing unit was greatly improved, benefiting from the high alignment accuracy. Parameter designs and simulations were carried out based on this sensing unit, which indicated that the sensitivities of the developed electrochemical seismometer decreased with the decrease in the number of flow holes in the sensing unit, and the initial stabilization time decreased gradually with the decrease in the thickness of the glass layer. Based on experimental results of four devices, the peak sensitivity was quantified as 5345.45 ± 43.78 V/(m/s) at 2 Hz, which proved high consistency of the fabricated electrochemical seismometer. In terms of the responses to random ground motions, high consistencies between the developed electrochemical seismometer and the commercial counterpart of CME6011 (R-sensors, Moscow, Russia) were found, where the developed electrochemical seismometer produced comparable noise levels to those of CME6011. These results validated the performance of the device and it may function as an effective tool for a variety of applications.

Influence of the Dielectric Coating of the Outer Side of the Cathode in the Anode–Cathode Pairs of a Molecular Electronic Sensitive Element on the Conversion Coefficient

“…Molecular electronic sensors of motion parameters and wave fields use miniature electrochemical cells as a sensitive element, in which the interelectrode current is very sensitive to external mechanical impact [ 1 , 2 , 3 , 4 ]. Highly sensitive motion sensors, such as seismometers, accelerometers and angular velocity sensors, have been created on the basis of such cells [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”

“…The success achieved in the technical characteristics and understanding of the broad commercial prospects of this direction, prompted researchers from around the world to develop technological solutions based on using precision methods of microfabrication, such as microelectronic fabrication and/or laser drilling [ 4 , 17 , 18 , 19 , 20 ], which reduce the scatter of parameters of sensitive elements, reduce their cost and prepare them for mass production. The first results related to the use of microelectronic technologies were published in 2012–2013 by research groups from Moscow Institute of Physics and Technology [ 21 ], Arizona State University [ 22 ] and the Institute of Electronics CAS [ 3 , 23 , 24 ].…”

“…In this case, the technological processes of oxidation in a diffusion furnace [ 21 ], explosive photolithography and electron–beam deposition [ 21 , 22 ], laser cutting [ 3 , 21 , 24 ], low-pressure chemical vapor deposited (LPCVD) [ 22 ], plasma-enhanced chemical vapor deposited (PECVD) [ 22 ], focused ion beam (FIB) [ 22 ], deep reactive ion etching (DRIE) [ 3 ], [ 22 ] were used. Over the next 10 years, these technologies were significantly developed and, nowadays, we can discuss the presence of several tested different solutions, which make it possible to successfully manufacture conversion elements with high sensitivity and good repeatability [ 4 , 17 , 18 , 19 , 20 ].…”

MEMS-Based Integrated Triaxial Electrochemical Seismometer

“…The sensitive electrodes of traditional commercial electrochemical seismometers were manufactured by platinum net-waving and ceramic sinter technologies, which suffered from fatal flaws of low yield, high cost, and poor consistency [12][13][14]. To solve these problems, MEMS technology was introduced to manufacture the sensitive electrodes of electrochemical seismometers in recent years [15][16][17][18][19][20][21][22][23].…”