Lifetime Enhancement under High Frequency NBTI measured on Ring Oscillators

Reliability engineering in RF CMOS

“…Experimental results concerning AC NBTI degradation reflect a similar disagreement on the frequency dependence of AC NBTI degradation. Different papers show a clear frequency dependence of NBTI degradation [44,45,46,47,48,49]. It has also been claimed that only the formation of positive oxide charge contributes to any frequency dependency, while interface state generation is frequency independent [50].…”

“…The frequency range discussed in these papers generally does not exceed the MHz range. Only in [49,53] NBTI degradation under RF stress conditions is discussed. In [49] use is made of a ring oscillator circuit and device parameter degradation is monitored indirectly using degradation in the oscillation frequency.…”

Device degradation and resilient computing

“…Once a node's performance has fallen below a predefined threshold, it has to go through the test & recovering phase in order to remove the impact of NBTI dominant stress from PMOS devices. Relaxation can be accomplished though AC load or the condition of V g = V DD [8], [12]. If after the test & recovering phase the performance degradation remains above a predefined threshold, the node is marked as broken.…”

Fast Wafer-Level Stress-and-Sense Methodology for Characterization of Ring-Oscillator Degradation in Advanced CMOS Technologies

“…P ERFORMANCE degradation of logic CMOS circuits, such as ring oscillators (ROs), is typically linked to the degradation mechanism in discrete devices, namely, bias temperature instability (BTI) and hot-carrier injection (HCI) [1]- [7]. With the introduction of metal gate/high-k (MG/HK) technologies, both nFET and pFET devices exhibit positive bias temperature (PBTI) and negative bias temperature instability (NBTI), respectively, while for conventional poly-Si/SiON technologies, only pFETs degrade due to NBTI stress.…”