Nano-electromechanical Switch Based on a Physical Unclonable Function for Highly Robust and Stable Performance in Harsh Environments

Abstract

A physical unclonable function (PUF) device using a nano-electromechanical (NEM) switch was demonstrated. The most important feature of the NEM-switch-based PUF is its use of stiction. Stiction is one of the chronic problems associated with micro- and nano-electromechanical system (MEMS/NEMS) devices; however, here, it was utilized to intentionally implement a PUF for hardware-based security. The stiction is caused by capillary and van der Waals forces, producing strong adhesion, which can be utilized to design a highly robust and stable PUF. The probability that stiction will occur on either of two gates in the NEM switch is the same, and consequently, the occurrence of the stiction is random and unique, which is critical to its PUF performance. This uniqueness was evaluated by measuring the interchip Hamming distance (interchip HD), which characterizes how different responses are made when the same challenge is applied. Uniformity was also evaluated by the proportion of "1" or "0" in the response bit-string. The reliability of the proposed PUF device was assessed by stress tests under harsh environments such as high temperature, high dose radiation, and microwaves.

Electrostatic pull-in application in flexible devices: A review

“…Boodhoo et al [ 38 ] investigated the influence of the doping level on the gate voltage by preparing bilateral-gate Si NW transistors. Figure 10 shows the NEM-PUF structure prepared by Hwang and co-workers [ 79 ]. The device uses Si NWs as a moving electrode and the two gates (G1/G2) are symmetrically distributed.…”

Physical unclonable function: architectures, applications and challenges for dependable security

“…Finite State Machine PUF (PUF‐FSM) proposed by Zhang , et al in [67] where the authors used employed FSMs to bind hardware IPs (HWIPs) to the FPGAs with PUFs to be used for IP protection. Nano‐electromechanical PUF (NEM‐PUF) is proposed by Hwang , et al in [68] where they exploited the mechanical actuation mismatches of a SiNW. In multiple‐valued logic PUF (MVL‐PUF) [69], Tao and Dubrova identified mismatches from the variation in current or voltage MVL comparators.…”

Inner Spacer Engineering to Improve Mechanical Stability in Channel-Release Process of Nanosheet FETs

“…However, both the above-mentioned approaches to form suspended channels encountered a mechanical instability, known as stiction, which is associated with the capillary force of chemicals during wet-etching [9]. Fortunately, this concern has been avoided by improved dry etching and supercritical drying [10][11][12][13]. The other concern during the suspension of channels is vertical stress associated with gravity.…”