Silicon Nanowires Driving Miniaturization of Microelectromechanical Systems Physical Sensors: A Review

Abstract

The miniaturization of microelectromechanical systems (MEMS) physical sensors is driven by global connectivity needs and is closely linked to emerging digital technologies and the Internet of Things. Strong technical advantages of miniaturization such as improved sensitivity, functionality, and power consumption are accompanied by significant economic benefits due to semiconductor manufacturing. Hence, the trend to produce smaller sensors and their driving force resemble very much those of the miniaturization of integrated circuits (ICs) as described by Moore's law. In this respect, with its IC‐, and MEMS‐compatibility, and scalability, the silicon nanowire is frequently employed in frontier research as the sensor building block replacing conventional sensors. The integration of the silicon nanowire with MEMS has thus generated a multiscale hybrid architecture, where the silicon nanowire serves as the piezoresistive transducer and MEMS provide an interface with external forces, such as inertial or magnetic. This approach has been reported for almost all physical sensor types over the last decade. These sensors are reviewed here with detailed classification. In each case, associated technological challenges and comparisons with conventional counterparts are provided. Future directions and opportunities are highlighted.

Simplified top-down fabrication of sub-micron silicon nanowires

“…Nanowires (NWs) are crucial building blocks of emerging optoelectronic and nanoelectromechanical systems (NEMS) [1][2][3][4]. Further miniaturization opportunities in CMOS integration [5] indicate NWs can provide significant improvements in NEMS [6][7][8][9][10][11][12].…”

“…With device dimensions shrinking to quantum limits, the fabrication or synthesis techniques of nanoscale features become increasingly challenging [13][14][15]. In addition to NEMS, microelectromechanical systems (MEMS) also benefit from downscaling for the development of on-chip integration of miniaturized smart sensors [1,2]. This leads to products with more intelligence and relatively low power consumption [1,2,16,17].…”

“…In addition to NEMS, microelectromechanical systems (MEMS) also benefit from downscaling for the development of on-chip integration of miniaturized smart sensors [1,2]. This leads to products with more intelligence and relatively low power consumption [1,2,16,17]. A number of candidate materials emerged in response to the available challenges, among which silicon (Si) NWs constitute a major subset due to compatibility with semiconductor manufacturing processes [1,2,13].…”

“…This leads to products with more intelligence and relatively low power consumption [1,2,16,17]. A number of candidate materials emerged in response to the available challenges, among which silicon (Si) NWs constitute a major subset due to compatibility with semiconductor manufacturing processes [1,2,13]. Thanks to their piezo resistivity and increased sensitivity to strain associated with reduced dimensions, Si NWs exhibit a promising potential in miniaturized inertial sensors [2,11,[18][19][20].…”

The Role of Native Oxide on the Mechanical Behavior of Silicon Nanowires

“…Nanowires (NWs) hold great promise as fundamental components for advancing future nanoelectromechanical systems [1], nanoelectronics [2,3], with notable applications in highly sensitive sensors [4][5][6] and cutting-edge energy technologies [7]. The remarkable advancements in fabrication methods [8,9], technological applicability [10], and multi-scale modeling techniques [11,12] have sparked great interest in the extensive characterization of NWs.…”