Underlying issues

Reducing MOS gate length and oxide thickness to a nanometric scale causes high variability, and increases the aging susceptibility of electronic devices. The manufacturers’ production tests ensure that the device you receive is functionally correct and resides within a given envelope in the parametric space, but it will never tell you what the actual margin for a given device is.

Aging phenomena such as negative or positive bias temperature instability (NBTI, PBTI) and hot carrier injection (HCI) are getting more critical and may affect the reliability of the product after a short operating time compared to the expected lifetime.

Reliability issues in nanometer CMOS technologies are mainly caused by the reduction of oxide thickness reaching atomic scales and the introduction of new materials and devices in order to reduce the exponential increase of leakage.