Switching oxide traps as the missing link between negative bias temperature instability and random telegraph noise

Abstract

Due to the ongoing reduction in device geometries, the statistical properties of a few defects can significantly alter and degrade the electrical behavior of nano-scale devices. These statistical alterations have commonly been studied in the form of random telegraph noise (RTN). Here we show that a switching trap model previously suggested for the recoverable component of the negative bias temperature instability (NBTI) can more accurately describe the bias and temperature dependence of RTN than established models. We demonstrate both theoretically and experimentally, that the recovery following bias temperature stress can be considered the nonequilibrium incarnation of RTN, caused by similar defects. We furthermore demonstrate that the recoverable component is solely constituted by individual and uncorrelated discharging of defects and that no diffusive component exists. Finally it is highlighted that the capture and emission times of these defects are uncorrelated.

Analysis of the relationship between random telegraph signal and negative bias temperature instability

“…However, when the stress is removed, α is decreased to its normal value. This implies that the traps responsible for RTS are also responsible for the NBTI recovery as reported in [21,22]. Note that Fig.…”

“…In fact, Kaczer et al pointed out a broad similarity between the relaxation process of NBTI and 1/f noise [21]. Furthermore, Grasser et al succeeded in reproducing the time constants of RTS by using a recovery model of NBTI [22], which indicates that care must be taken to properly account for these two phenomena for worst-case SRAM design margins.…”

Analysis of defect capture cross sections using non-radiative multiphonon-assisted trapping model

“….Þ have been taken from measurement values based on scanning tunneling spectroscopy studies for single-defect Si dangling bonds [25]. The dynamics of other oxide traps (E c and E d [7,32]) are better described including metastable states [11,24]. However, EPR studies indicated that these defects relax almost immediately after the removal of the stress condition [9], and thus they have not been investigated in this study.…”

“…Recently, correlation has been found between Random Telegraph Noise (RTN) and Negative Bias Temperature Instability (NBTI), by considering interface and oxide defects having a wide spread distribution of capture/emission (C/E) rates [12]. It has also been shown that the trapping dynamics of single defects are playing a major role in the phenomena [11], while C/E transitions have been attributed to multiphononassisted mechanisms [13]. For these reasons, increasing effort has been applied to the determination of the relationship between the macroscopic time constants and the microscopic variables predicted by multiphonon theory.…”

“…The amphoteric nature of P b centers is responsible of the altered electrical characteristics as the defects act both as electron donor and acceptor impurities [9,10]. Nevertheless, the relation between microscopic physical aspects and macroscopic effects on the electrical characteristics is still under debate [11]. Recently, correlation has been found between Random Telegraph Noise (RTN) and Negative Bias Temperature Instability (NBTI), by considering interface and oxide defects having a wide spread distribution of capture/emission (C/E) rates [12].…”