(A) novel nanoelectromechanical switching device for ultra-low power ic and harsh environment electronics

Abstract

Nanoelectromechanical (NEM) switches have received widespread attention as promising candidates in the drive to surmount the physical limitations currently faced by complementary metal oxide semiconductor technology. The NEM switch has demonstrated superior characteristics including quasi-zero leakage ehavior, excellent density capability and operation in harsh environments. However, an unacceptably high operating voltage (4-20 V) has posed a major obstacle in the practical use of the NEM switch in low-power integrated circuits. To utilize the NEM switch widely as a core device component in ultralow power applications, the operation voltage needs to be reduced to 1 V or below. However, sub-1 V actuation has not yet been demonstrated because of fabrication difficulties and irreversible switching failure caused by surface adhesion. Here, This dissertation reports the sub-1 V operation of a NEM switch through the introduction of a novel pipe clip device structure and an effective air gap fabrication technique. This achievement is primarily attributed to the incorporation of a 4-nm-thick air gap, which is the smallest reported so far for a NEM switch generated using a ‘top-down’ approach. The proposed structure and process can potentially be utilized in various nanogap-related applications, including NEM switch-based ultralow-power integrated circuits, NEM resonators, nanogap electrodes for scientific research14 and sensors. Also, as a feasible application for the 2-terminal NEM switch, this thesis suggests the mechanical memory device that can be used as reconfigurable switches in field-programmable gate-array (FPGA) for harsh environment applications. An electrothermal actuation enables the NEM device to perform reliable memory operation in high temperature (at 400℃) and sub-1 V actuation. The measurement result shows the excellent device-to-device uniformity and highly reliable memory characteristics even in a harsh condition, which cannot be conducted by semi...