Reliability and Fatigue Analysis in Cantilever-Based MEMS Devices Operating in Harsh Environments

Table 1

Summarizes various MEMS groups, their causes of failure, and procurement of the failures.

Group	Causes of failure/reliability issues	Test	Reference
Group 1
DNA sequencers; Microfludic; nozzles; Chemical sensor	Dielectric breakdown	2×4 microfludic array, X and Y direction electrodes were shorted, respectively; the effects of changes on the electrodes were simulated, and transportation of droplets was observed by CCD Camera.	[69]
Group 1 or 2
Accelerometer	Mechanical wear, fracture, fatigue, charging, change in friction	(1) Built in self repairable tests within the device were reported. Comparison of BISR and Non-BISR MEMS; simulation of fatigue and S-N (no. of cycles to failure) curve; (2) Accelerated life time experimental tests were performed for 1000 hours at about 145° to 200°C.; (3) Fatigue testing using Tytron 250. The experimental fatigue life lines were between 7.78×10^4 to 1.48×10^7 cycles at the stress levels of 2.05 to 2.83 GPa.; (4) Sandia National Laboratories have developed the Sandia High volume Measurement of Micromachine Reliability (SHiMMeR) to control and measure up to 256 MEMS parts, simultaneously; it is a Plexiglas enclosure with a high power optical microscope and cameras.; (5) Military Test Standard Device (MIL-STD-883F) for stiction, Diamond Like Carbon (DLC coating) for wear, X-rays diffraction for fatigue and creep, and for contamination Scanning acoustic Microscope (SAM)	[28–30, 33, 34]
Group 2
Pressure sensors	Fracture, fatigue, shock, vibrations, and change in friction	Sensors were designed and manufactured well below the stress level where fatigue was detected in silicon; fatigue in pressure sensor occurred when stress and fracture levels were almost equal.	[35]
Gyroscopes	Charging, shock, and vibrations	(1) Adhesion failure mode in lateral capacitive gyroscope was experimentally analyzed.; (2) Variations in noise and signal out as well as temperature degradations were reported.	[36, 37]
Group 3
Thermal actuator	Mechanical wear, shock, and vibrations	(1) Fracture experimental tests were performed by applying load on the beam using Weibull statistics.; (2) Experimental methodology for the evaluation of creep in microswitches based on the deformation of the switch due to charging and due to creep.; (3) Pull-in voltages were observed in bend and torsinol modes. fatigue tests were carried out and the predicted life time reported was 10^11cycles.	[70–72]
Valves	Mechanical wear, fracture, fatigue, shock, and vibrations	(1) Design issues were classified; more research is needed for better understanding.; (2) Fatigue test of thick aluminum specimen was observed in liquid environment.	[31, 73]
Micro relays	Mechanical wear, fracture, fatigue, shock, vibrations, and charging	10^9 on/off switching cycles without stiction and welding induced failure were reported.	[32]
Group 4
Electrostatic actuator	Mechanical wear, fracture, fatigue, shock, vibrations, and charge in friction	Analysis of pull-in and pull-out voltages using stochastic modeling for prediction of life time of devices	[39, 74, 75]
Optical shutter	Mechanical wear, fracture, fatigue, shock, and vibrations	Imprecise data availability
Mirror device	Mechanical wear, fracture, fatigue, shock, vibrations, and optical degradation	Texas Instruments (TI) developed the MirrorMaster, a custom optical inspection tool for DMD devices that inspects every pixel of the DMD array and determines the response of each pixel to different electrical drive signals.	[7]
Gear devices	Mechanical wear, fracture, fatigue, shock, vibrations, and charge in friction	Simulations of sliding surfaces prevented adhesion and wear	[76]
Microturbine/fan	Mechanical wear, shock, vibrations, and charge in friction	Imprecise data availability