Random telegraph signals originating from unrelaxed neutral oxygen vacancy centres in SiO ₂

Abstract

Unrelaxed neutral oxygen deficiency centres (ODCs) (V 0 ODC II) in SiO 2 have been identified as the cause of random telegraph signals (RTSs) in highly scaled n-type metal-oxide-semiconductor fieldeffect transistors. Variable temperature RTS measurements were performed to extract trap capture cross-sections, capture activation energy, relaxation energy associated with the gate oxide defects, and the trap energy in the SiO 2 bandgap to determine the trap species and type. The results indicate that the electron is captured by a neutral ODC that is transformed into a negatively charged vacancy (V −). This is the first time V 0 ODC II centre is confirmed to be the source of electron switching through RTS measurements defining four different trap characteristics.

A Stand-Alone, Physics-Based, Measurement-Driven Model and Simulation Tool for Random Telegraph Signals Originating From Experimentally Identified MOS Gate-Oxide Defects

“…In an earlier publication [27], we demonstrated that these E R and E B values are indicative of unrelaxed neutral oxygen deficiency centers (V 0 ODC II) that become repulsive centers upon capturing an electron (Fig. 6) [17], [27], [44], [45].…”

“…3. In general, average times associated with the traps located further deep in the oxide bulk show stronger dependence on V GS than those associated with the traps closer to the Si/SiO 2 interface [27], [42].…”

“…Here, f t is the trap occupancy function. The traps responsible for the switching events in these nMOSFETs were identified to be an acceptor type [27]. The V GS and temperature dependence of experimentally obtainedτ c andτ e are shown in Fig.…”

“…Most nMOSFETs have been shown to exhibit RTS due to acceptor traps [16], [24], [27]. However, there have been few reports of donor traps and of RTS due to multiple traps whose occupancy depends on each other [24], [27]- [29].…”

“…However, there have been few reports of donor traps and of RTS due to multiple traps whose occupancy depends on each other [24], [27]- [29]. Based on our and other published data, RTSSIM is set to recognize three different trap types: 1) acceptor (A) [16], [24], [27]; 2) two dependent acceptors (AA) [24], [29]- [33]; and 3) donor (D) [24], [28], [34]. User can choose a single species (A, AA, or D) or one of the nine permutations (such as A from the first set of options and AA from the second set of options or D from the first set and A from the second set) of the two trap species to simulate RTS.…”