Threshold voltage asymmetric degradation on octagonal MOSFET during HCI stress

To improve analogue circuit reliability, the evolution of V_T and V_T matching under hot carrier injection (HCI) stress has been investigated on standard and octagonal MOSFETs. An important degradation can be observed on standard devices due to the presence of parasitic corner transistors. The specific structure of octagonal MOSFETs removes parasitic transistors and reduces V_T degradation. Moreover, the residual V_T degradation of octagonal MOSFETs, which is asymmetric, is further reduced by reversing source and drain connections.