Fabrication of a MEMS switch with robust metal contact
Project description
The project Fabrication of a MEMS switch with robust metal contact aims to improve the lifetime of MEMS from switching applications by investigating the contact degradation mechanisms at nanoscale and it integration in a chevron structure. Such an approach can be achieved after introducing the following targeted innovations: (1) Deep understanding based on characterization results achieved on switch contact materials; (2) Development of an original model of reliable MEMS switch; (3) Validation of MEMS switch prototype and its implementation.

Figure 1.
Schematic design of MEMS switch:
(a) top-view; (b) off-state; (c) on-state.

This project is orientated to characterizations of MEMS switches contact considering an atomistic analysis of the tribomechanical properties of surfaces and materials. Accelerated tests of MEMS switches developed in this project and overall characterizations of the materials and electrodes surfaces during cohesion will lead to lifetime prediction of the investigated devices. A micro electrothermal actuation provides high force and long traveling distance. The metallic structure can be used either as a metal-to-metal switch or as a thermal sensor. The movable electrode is moved to the fixed electrode in the analysed case by thermal expansion of beams (chevron actuator) as presented in figure 1. Monolithic integration with electrical circuit is considered for fabrication process of switches. The coplanar waveguide (CPW) is under and along the mobile electrode (Fig.1a). The cross-section of the switch in the off-state position is shown in Fig.1b. When a thermal gradient is applied to the structure the mobile electrode moves towards the fixed electrode and the switch is in the on-state (Fig.1c). The main failure causes are contact fatigue based on cohesion and stiction. The scope of research work is to fabricate a reliable MESM switch with metallic contact and high lifetime.
2016 - 2018
Proiect finantat de UEFISCDI 
Proiect experimental - demonstrativ 33PED/ 2017
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