Accelerometers are the most common inertial sensors in the rapidly developing market due to their small size, high sensitivity and low cost. It has been widely used in engineering monitoring, medicine, navigation, transportation, consumer electronics and other fields. IntelliSuite software can realize the complete design flow of various MEMS devices from layout design, process design to device performance design and system design.

Capacitive accelerometers detect the acceleration of an object using small changes in the capacitance of a capacitor

Usually, the structure of capacitive accelerometer includes a movable central mass, which generates inertial force under the action of external acceleration, the spring fixed on the rigid frame provides support for the central mass, and the capacitive electrode fixed on the rigid frame A variable capacitor is formed with the capacitive electrodes on the central mass. The change of acceleration can be converted into the change of inertia force and then into the change of capacitance, and the change of capacitance can be detected by the microelectronic circuit. The basic structure of capacitive accelerometer is shown in the figure. Compared with other types of MEMS accelerometers, capacitive accelerometers have the advantages of high sensitivity, low power consumption, low noise, stable DC characteristics and small temperature dependence. Using IntelliSuite software, the design process of capacitive accelerometer is realized through system-level design, process process and device performance simulation analysis.

Figure 1. Structure diagram of capacitive accelerometer

system level design

(a) Capacitive accelerometer system model 

(b) AC analysis results

(a) Transient analysis results

Extract layout files

Select Synthesis ...Synthesize Mask Layout to generate capacitive accelerometer layout file

Process flow

Design process flow with IntelliFab modules

Process simulation

Physical-level process simulation with the FabSim module

Production of 3D models

Generate 3D models from layout files with 3D Builder

Export 3D model

Export analysis model from 3DBuilder, open in TEM

Device level simulation 

(a) Frequency analysis results

(b) Dynamic analysis results

Comparison of system-level analysis and device-level analysis results

(a) Y displacement

(b) Capacitance