A Bistable Electrostatic Silicon Nanofin Relay for Nonvolatile Memory Application

Abstract

We present a nanoelectromechanical (NEM) relay that is capable of demonstrating two stable states without on-hold power due to the influence of van der Waals force. This is realized by leveraging a silicon nanofin (SiNF) as a relay that can switch between two lateral terminals. The smallest dimension of the SiNF is 80-nm width by 2-μm length. The SiNF is able to maintain its geometrical position even after the bias voltage is turned off. Bistable hysteresis behavior with pull-in voltage (V PI ) and reset voltage (V RESET ) as low as 8.4 and 10.1 V is measured. The nanoscale footprint of this device shows great potential for high-density nonvolatile memory applications.[ 2013-0109]Index Terms-Nanoelectromechanical systems, relay, switch, van der Waals, nonvolatile memory, Bistable, electrostatic. I. IntroductionThe ever quest in CMOS scaling has expanded the exploration boundary beyond conventional transistor, listing from quantum devices, ultrathin body silicon on insulator (SOI), fin-FET, and so on. Most devices leverage on the transportation of electrons or the same to determine the on-off criteria [1], [2]. Until recently, nanoelectromechanical (NEM) relay has drawn great attention due to its exceptional properties. NEM relay is a physically actuated nanoscale mechanical switch that does not rely on transportation or storage of charges. Instead, NEM relay relies on mechanical switching motion and geometrical shape to replicate logic operation in transistor and solid state nonvolatile memory (NVM) and its advantages include extremely low off-state leakage current, steep sub-threshold slopes, and capability of high temperature operation [3]- [5]. It is already reported that the NEMS relay can complement CMOS circuits resulting in faster operation and erasing speed [6], [7]. Besides that, reports suggest that the NEM switches can overcome poor performance usually at the extremes of temperature because of their mechanical switching nature

Nanoelectromechanical relay without pull-in instability for high-temperature non-volatile memory

“…Table 1 compares the performance of previously reported electrostatically actuated non-volatile relays with the presented relay. To the best of our knowledge, only Soon et al 14 have reported more than 1 or 2 reprogramming cycles to date; they demonstrated 11 cycles at 50°C with a programming voltage of 10 V and reprogramming voltages between~12 and 15 V. We achieved a programming voltage…”

“…Non-volatile memory requires relays that retain the switched state when power is switched off. Electrostatically operated NEM relays reported in the literature for both volatile operation 5,9,6,7,[10][11][12] and non-volatile operation [12][13][14] have architectures including a beam anchored at one end (cantilever), both ends (bridge), the centre (see-saw) and at four corners (crab leg), with different types of hinges. When actuated, the beam moves under an electrostatic force to make contact with a stationary electrode to establish the 'on' state.…”

“…Further, contacts deteriorate faster with heavy impacts, of particular concern in non-volatile relays that use contact adhesion forces to achieve bistability. Thus, only a very small number of reprogramming cycles have been demonstrated for bistable relays to date [13][14][15][16] , which highlights the challenge in realising reliable non-volatile operation.…”

Nonvolatile Nanoelectromechanical Memory Switches for Low-Power and High-Speed Field-Programmable Gate Arrays

“…3(a) shows the structure of a NEM memory switch for FPGA applications. Its operation principle referring to [7] and [8] has already been confirmed experimentally [10]. It consists of two metal line electrodes, which are called selection line 1 (L 1 ) and selection line 2 (L 2 ), respectively, and a movable cantilever beam attached to the bit line (BL), which switches between L 1 and L 2 .…”

All metal nanoelectromechanical switch working at 300 °C for rugged electronics applications

“…This unique mechanically controlled feature endows NEM switches with several important properties for logic computation and non-volatile memory applications, which are unavailable in traditional CMOS technology, such as near zero subthreshold swing and hysteresis switch behavior. [15][16][17][18] As long as the structural and contact materials maintain their electrical and mechanical properties, the devices will be functional as designed in a high temperature environment. However, challenges still remain for recently reported M/NEM switches.…”