Universality of Off-State Degradation in Drain Extended NMOS Transistors

Off-state degradation in drain extended NMOS transistors is studied. It is shown that the damage is primarily due to Si-O bonds broken by hot carriers. These hot carriers are generated through impact ionization of surface band-to-band tunneling (BTBT) current. The resultant degradation is found to be universal, enabling reliability projections at lower stress voltages and based on shorter duration tests, than previously anticipated