High‐power MEMS switch enabled by carbon‐nanotube contact and shape‐memory‐alloy actuator

Abstract

A forest of vertically aligned carbon nanotubes (CNTs) is integrated as an electrical contact material with a high-power, normally-open switch based on micro-electro-mechanical systems (MEMS) technology. A shape-memory-alloy (SMA) cantilever is thermally actuated to enable switching between the movable CNT forest and the copper electrode formed on the SMA. The out-of-plane SMA actuator provides high forces to enable distributed contacts with the CNT forest, achieving low contact resistances and high ON/OFF resistance ratios. The ON state of the switch shows contact resistances as low as 35 V with a dependence on the operating current. The device operation is performed with over 5-W input powers. Long-term operation with more than 1 Â 10 6 switching cycles is demonstrated. The results indicate that a combination of the CNT-based contact and the SMA actuator may be a promising path to realizing reliable MEMS contact switches for high-power applications.

Anomalous Behavior During Nano‐Compression Superelastic Tests on Cu‐Al‐Ni Shape Memory Alloy Micro Pillars

“…The advent of the trend of miniaturization has led to focus research efforts on SMA at the micro and nano metric scale, seeking to obtain active components that can be used in the development of new and sophisticated sensors and actuators that can be framed in the concept of the smart micro electro‐mechanical systems (SMEMS), or its nanometric analogs, the SNEMS. In this sense, most efforts were made in the production and characterization of SMA thin films, from which many devices such as microwrappers, microgrippers, microcages, microvalves and micro switch, among others, were already developed for MEMS applications; see the reviews in this field . However, these thin‐film based technologies present at least one dimension, and in most of cases two dimensions, in the order of the millimeter.…”

Micromachined Shape-Memory-Alloy Microactuators and Their Application in Biomedical Devices

“…It is common to fabricate cantilever type actuators by using an SMA sheet because of the high actuation force compared with thin-film SMA. The two-way actuation can be obtained through mechanical TWSME [1], such as depositing a reset layer (SiO2 or Si3N4) on the SMA [92][93][94], as shown in Figure 6, or by using intrinsic TWSME [25]. The actuation is normally performed using Joule heating by passing the current through the SMA itself.…”

Adaptive predictive control of a novel shape memory alloy rod actuator

“…The mentioned traits have been making them appealing to scientists from an eclectic realm including automotive, 3–9 robotics, 10–14 and medicine. 15–23 More specifically, SMAs are used in the development of mechanical couplings, 24 mechanical actuators, 25–29 grippers, 30–33 micro-pumps, 34 microvalves, 35 control 36–42 and vibration of structures, 43–46 sensors, 47 and the like.…”