Piezoelectrically Actuated Linear Resonators on Ring-shaped Suspensions for Applications in MEMS Phase-sensitive Gyroscope

AbstractExcitation of linear resonators by means of thin aluminium nitride piezoelectric films processed on annular (ring-shaped) flexures was investigated. The in-plane resonance modes at 8-45kHz frequencies with quality factors >104 were measured for both single (uni-directional) and double (bi-directional) in-plane degree of freedom devices in vacuum. Annular springs have different spring constants for different directions of deformation allowing efficient decoupling of orthogonal modes in bi-directional symmetric devices. The primary application of the bi-directional resonators is in orbiting-motion MEMS gyroscopes that rely on phase-shift detection induced by external angular rates. To investigate the feasibility of differential piezoactuation for generation of motion in uni- and bi-directional devices by means of thin piezoelectric films processed on supporting annular springs, MEMS resonators were modelled, designed, fabricated and electrically characterized

Statistical Model Selection for TID Hardness Assurance

Radiation Hardness Assurance (RHA) methodologies against Total Ionizing Dose (TID) degradation impose rigorous statistical treatments for data from a part's Radiation Lot Acceptance Test (RLAT) and/or its historical performance. However, no similar methods exist for using "similarity" data - that is, data for similar parts fabricated in the same process as the part under qualification. This is despite the greater difficulty and potential risk in interpreting of similarity data. In this work, we develop methods to disentangle part-to-part, lot-to-lot and part-type-to-part-type variation. The methods we develop apply not just for qualification decisions, but also for quality control and detection of process changes and other "out-of-family" behavior. We begin by discussing the data used in the study and the challenges of developing a statistic providing a meaningful measure of degradation across multiple part types, each with its own performance specifications. We then develop analysis techniques and apply them to the different data sets