Integrated otpical monitoring of MEMS for closed-loop control

Abstract

Robust control and failure assessment of MEMS employed in physically demanding, mission critical applications will allow for higher degrees of quality assurance in MEMS operation. Device fault detection and closed-loop control require detailed knowledge of the operational states of MEMS over the lifetime of the device, obtained by a means decoupled from the system. Preliminary through-wafer optical monitoring research efforts have shown that through-wafer optical probing is suitable for characterizing and monitoring the behavior of MEMS, and can be implemented in an integrated optical monitoring package for continuous in-situ device monitoring. This presentation will discuss research undertaken to establish integrated optical device metrology for closed-loop control of a MUMPS fabricated lateral harmonic oscillator. Successful linear closed-loop control results using a through-wafer optical microprobe position feedback signal will be presented. A theoretical optical output field intensity study of grating structures, fabricated on the shuttle of the resonator, was performed to improve the position resolution of the optical microprobe position signal. Throughwafer microprobe signals providing a positional resolution of 2 m using grating structures will be shown, along with initial binary Fresnel diffractive optical microelement design layout, process development, and testing results. Progress in the design, fabrication, and test of integrated optical elements for multiple microprobe signal delivery and recovery will be discussed, as well as simulation of device system model parameter changes for failure assessment.

Structure Rotation and Pull-in Voltage Control of MEMS Lateral Comb Resonators Under Fault Conditions

“…Let and , then matrix is defined as (21) where is the solution of the following algebraic Ricatti equation: (22) where and are arbitrary positive definite matrices that satisfy (22) along with , and the gain-switching matrix is defined as (23) where is such that the equation…”

“…6. Readers that are interested in data-recovery technique and instantaneous displacement monitoring are referred to [22] and [23] VIII. EXPERIMENTAL RESULTS AND DISCUSSION…”