Random telegraph noise in 2D hexagonal boron nitride dielectric films

Abstract

This study reports the observation of low frequency random telegraph noise (RTN) in a 2D layered hexagonal boron nitride dielectric film in the pre- and post-soft breakdown phases using conductive atomic force microscopy as a nanoscale spectroscopy tool. The RTN traces of the virgin and electrically stressed dielectric (after percolation breakdown) were compared, and the signal features were statistically analyzed using the Factorial Hidden Markov Model technique. We observe a combination of both two-level and multi-level RTN signals in h-BN, akin to the trends commonly observed for bulk oxides such as SiO2 and HfO2. Experimental evidence suggests frequent occurrence of unstable and anomalous RTN traces in 2D dielectrics which makes extraction of defect energetics challenging.

Tunnel spectroscopy of localised electronic states in hexagonal boron nitride

“…This observation of a three-step tunnelling transition process is of topical interest as it is an example of a percolation process, which has been recently reported in refs. 43,44 . Fig.…”

Boron Vacancies Causing Breakdown in 2D Layered Hexagonal Boron Nitride Dielectrics

“…Hexagonal boron nitride (h-BN) is a promising 2D layered insulator with high thermal, mechanical and chemical stability, matching lattice constant to graphene and a van der Waals structure that allows for easy integration and realization of fully-2D nanodevices. There have been a few recent reports on h-BN from a reliability perspective which have: measured the breakdown (BD) field strength [1]; probed the electrical defects using random telegraph noise techniques [2,3]; provided physical evidence of the sequential removal of layers during BD with a Weibull distribution to represent BD statistics; observed pit formation in multi-layer h-BN after BD [4]; suggested the presence of bimodality in the progressive BD trends due to competition between lateral wear-out and multi-layer BD [5]; examined the resonant electron tunneling and electron percolation through local bandgap states within h-BN [6]; and studied the charge trapping and impact ionization phenomena in h-BN at low and high fields [7]. However, there is a lack of insight into the statistical nature and defect chemistry of BD in h-BN [8], which is the focus of this study.…”

Emerging Scanning Probe–Based Setups for Advanced Nanoelectronic Research

“…In its origin CAFM, was mainly used to characterize the electrical properties of thin (<50 nm) dielectric materials (i.e., SiO 2 , HfO 2 , Al 2 O 3 ) at nanoscale. More specifically, the CAFM can be used to study tunneling current, polycrystallization, charge trapping and de‐trapping, random telegraph noise, stress induced leakage current (SILC), dielectric breakdown, and resistive switching . Recently, its use has also expanded to other low‐dimensional materials, such as nanowires (NWs), carbon nanotubes (CNT), nanodots, and 2D materials .…”