Effect of stress on the pull-in voltage of membranes for MEMS application

Abstract

In this work, the effect of process residual stress has been studied on three different designs of membranes for RF MEMS switch application. Expressions for the pull-in voltage of stressed membranes have been developed by simple modification of existing relation for unstressed membranes. To validate the results, gold membranes have been fabricated and released successfully using silicon dioxide as the sacrificial layer. The theoretical results show a very good match with experimental results. This expression allows the estimation of the pull-in voltage of stressed membranes without the need for numerical simulations. The stress in the membranes can also be extracted from pull-in voltage measurements. Our results show that high spring constant (K) structures are less prone to deflection and change in the pull-in voltage. Also, for a high stress value, the pull-in voltages of the structures become almost independent of the spring constant.

Effect of pressure on nonlinear dynamics and instability of electrically actuated circular micro-plates

“…It should be noticed that in Eq. (16), if V DC = 0, the actuation load is proportional to (V AC sin(ωt)) 2 , which means the actual excitation frequency is equal to (2 ). Therefore, resonance is observed at /ω 0 = 0.5.…”

Estimating residual stress, curvature and boundary compliance of doubly clamped MEMS from their vibration response

“…The β 4 2 surface fit has a maximum error of 2.05% and an average error of 0.25% when compared to the numerically calculated values. The β 4 4 surface fit has a maximum error of 4.93% and an average error of 1.29% when compared to the numerically calculated values. The fits are We now have a functional form for the natural frequencies of the two lowest antisymmetric transverse bending modes, in the form of β 4 n = F (α 2 , log 10 (T )), where α 2 is proportional to the residual stress and T is proportional to the boundary compliance.…”

“…The functional form of the fit is provided in appendix B, along with the calculated coefficients. Here we have fitted to the quartic of the non-dimensional frequency β n , that is we have fitted to β 4 n . The β 4 2 surface fit has a maximum error of 2.05% and an average error of 0.25% when compared to the numerically calculated values.…”

“…Here we have fitted to the quartic of the non-dimensional frequency β n , that is we have fitted to β 4 n . The β 4 2 surface fit has a maximum error of 2.05% and an average error of 0.25% when compared to the numerically calculated values. The β 4 4 surface fit has a maximum error of 4.93% and an average error of 1.29% when compared to the numerically calculated values.…”

“…Broadly speaking microscale mechanical tests for estimating system parameters can be grouped into three categories: pull-in/electrical [3,2,4], static mechanical [5][6][7][8] and dynamic mechanical [9][10][11][12][13][14][15]. Methods in the first category rely on pull-in voltage information or electrical characterizations to obtain microsystem parameters.…”