A capacitive CMOS–MEMS sensor designed by multi-physics simulation for integrated CMOS–MEMS technology

Abstract

This paper reports the design and evaluation results of a capacitive CMOS–MEMS sensor that consists of the proposed sensor circuit and a capacitive MEMS device implemented on the circuit. To design a capacitive CMOS–MEMS sensor, a multi-physics simulation of the electromechanical behavior of both the MEMS structure and the sensing LSI was carried out simultaneously. In order to verify the validity of the design, we applied the capacitive CMOS–MEMS sensor to a MEMS accelerometer implemented by the post-CMOS process onto a 0.35-µm CMOS circuit. The experimental results of the CMOS–MEMS accelerometer exhibited good agreement with the simulation results within the input acceleration range between 0.5 and 6 G (1 G = 9.8 m/s2), corresponding to the output voltages between 908.6 and 915.4 mV, respectively. Therefore, we have confirmed that our capacitive CMOS–MEMS sensor and the multi-physics simulation will be beneficial method to realize integrated CMOS–MEMS technology.

Structure stability of high aspect ratio Ti/Au two-layer cantilevers for applications in MEMS accelerometers

“…The deformation was found to be higher with an increase in length of the micro-cantilevers. This is because shear force at the fixed-end would increase with an increase in the length according to the Euler-Bernoulli beam theory for cantilever beam with uniformly distributed load [6].…”

“…Recently, complementary metal-oxide-semiconductor-micro-electrical-mechanical system (CMOS-MEMS) technology has been developed to design electronic devices with an improved performance [4,5]. Thus, we have developed the high sensitive micro-electro-mechanical system (MEMS) inertia sensor and the integrated CMOS-MEMS accelerometer using gold material as proof mass [6][7][8]. In order to realize the CMOS-MEMS structure, a post-CMOS process that would not affect the CMOS properties is required.…”

“…Young's modulus of titanium is 120.2 GPa [12]. The structure stability has been reported to be improved using a thin titanium layer as the bottom layer in a two-layer Ti/Au structure [6][7][8]. In addition, the titanium layer can also be used to improve adhesion of the gold layer on SiO 2 .…”

Development of high sensitivity CMOS-MEMS inertia sensor and its application to early-stage diagnosis of Parkinson's disease

“…The reason why large-scale integrated circuit (LSI) designer can design the circuit is that design environment and design kit are provided to the designer. We have developed CMOS-MEMS multi-physics design environment [19]. Figure 7 shows an equivalent circuit of a MEMS capacitive accelerometer for the multi-physics design environment.…”

Effect of heater geometry and cavity volume on the sensitivity of a thermal convection-based tilt sensor

“…In recent years, different studies have presented several methods for measuring the tilt orientation of devices. [11][12][13][14][15][16] One of the techniques for measuring the horizontality of a moving object is to put a water droplet in a glass pipe and observe any changes in the water droplet's position caused by tilting. These conventional water droplet tilt sensors have certain drawbacks.…”