Characterization of the Piezoresistive Effects of Silicon Nanowires.

Seohyeong Jang,Hyoungho Ko,Kyo-In Koo,Dong-Il Cho,Jinwoo Sung,Bobaro Chang,Taeyup Kim

doi:10.3390/s18103304

Abstract

Silicon nanowires (SiNWs) have received attention in recent years due to their anomalous piezoresistive (PZR) effects. Although the PZR effects of SiNWs have been extensively researched, they are still not fully understood. Herein, we develop a new model of the PZR effects of SiNWs to characterize the PZR effects. First, the resistance of SiNW is modeled based on the surface charge density. The characteristics of SiNW, such as surface charge and effective conducting area, can be estimated by using this resistance model. Then, PZR effects are modeled based on stress concentration and piezopinch effects. Stress concentration as a function of the physical geometry of SiNWs can amplify PZR effects by an order of magnitude. The piezopinch effects can also result in increased PZR effects that are at least two times greater than that of bulk silicon. Experimental results show that the proposed model can predict the PZR effects of SiNWs accurately.

Highlights

Silicon nanowires (SiNWs) have attracted attention for various applications, such as sensors [1,2], electronic devices [3,4,5,6], and microelectromechanical systems [7,8,9] due to their small dimensions and large surface-to-volume ratio
The stress concentration effects were as aoffunction of the physical geometry of SiNWs, thatlocal the local were effects modeled asmodeled a function the physical geometry of SiNWs, whichwhich meansmeans that the stress in stress in SiNWs was different from the global stress in the substrate
The piezopinch effects were modeled by modeled by a stress-induced change for a conducting channel in SiNW, similar to the voltagea stress-induced change for a conducting channel in SiNW, similar to the voltage-induced pinch-off induced pinch-off phenomenon in a metal-oxide-semiconductor field-effect transistor (MOSEFT)

Summary

Introduction

Silicon nanowires (SiNWs) have attracted attention for various applications, such as sensors [1,2], electronic devices [3,4,5,6], and microelectromechanical systems [7,8,9] due to their small dimensions and large surface-to-volume ratio. Two types of model, based on quantum confinement effects and surface charge effects, respectively, have been the main focus of research to explain the PZR effects of SiNWs. Some research has proposed a model based on quantum confinement effects to demonstrate the origin of the PZR effects of. The giant PZR effects were explained by a change of the effective mass of carriers [11]. An interplay between the heavy and light holes of the surface layer can change the effective mass, which induces the PZR effects in SiNWs. A strain-induced bandgap shift was described as the primary cause of the PZR effects [12]. The carrier mobility of SiNWs with respect to the stress was investigated [13]

Methods

Results

Conclusion