Mechanism of negative-bias-temperature instability

Abstract

Although negative-bias-temperature instability in metal-oxide-semiconductor integrated circuits has been minimized empirically, the exact mechanism is unknown. We argue in this paper that the mechanism of negative-bias-temperature instability can be modeled by a first-order electrochemical reaction between hydrogenated trivalent silicon, a neutral water-related species located in the oxide near the Si-SiO2 interface, and holes at the silicon surface to form neutral trivalent silicon and a positively charged water-related species. To show that such a reaction describes the phenomenon, we show that (1) water must be present in the oxide near the Si-SiO2 interface, (2) induced interface and oxide-fixed charge densities are equal, (3) the saturation interface-trap and oxide-fixed charge densities depend on the initial hole concentration at the silicon surface or aging field, (4) the buildup of these charge densities follows first-order reaction kinetics, and (5) time constants for this charge buildup are independent of aging field. The measurements which are done to demonstrate these features combine room-temperature charge measurement using the Q-C method with current measurements during accelerated aging.

SiO2/SiC structures annealed in D218O: Compositional and electrical effects

“…25 Besides, device instabilities were attributed to the presence of water-related species in SiO 2 /Si structures. 26 These effects highlight the importance of understanding the interaction of water vapor with SiO 2 /SiC and SiO 2 /Si. In fact, we have reported 27,28 that the substrate plays an important role in water vapor interaction with SiO 2 films thermally grown on SiC and on Si: in the SiO 2 /SiC case, hydrogen was observed to be incorporated in the surface, bulk, and interfacial region of the SiO 2 film, while in the SiO 2 /Si case hydrogen was mainly incorporated in the near-surface region of the SiO 2 film.…”

A study of negative-bias temperature instability of SOI and body-tied FinFETs

“…This study is primarily focused on the reliability of a doublegate FinFET with 2.1-nm gate oxide. We analyze the NBTI characteristics using electrochemical reaction models at the silicon/silicon dioxide interface as reported in previous work [8], [9]. The interface defects (hydrogen-passivated dangling silicon bonds) are electrically activated by holes at the SiO Si interface, and active interface traps and positive fixed oxide charges are left, while electrons are diffused toward the center of the fin or the silicon bulk.…”

Comparative Analysis of Channel Length Dependence of NBTI and CHC Characteristics in PMOSFETs

“…반전 동작 (inversion operation) 시, pMOSFET의 채널 영역에 있는 정공들에 의해 NBTI 에 의한 특성 열화가 발생한다 [5]. 고온에서 이 정공 들로 인해 Si-H 결합이 깨지게 되며, 절연체 내에 fixed oxide charge가 형성되기도 한다 [2].…”