IDENTIFICATION OF FIXED AND INTERFACE-TRAP CHARGES IN HOT-CARRIER STRESSED METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTORS (MOSFETS) THROUGH ULTRAVIOLET-LIGHT ANNEAL AND GATE CAPACITANCE MEASUREMENTS

Fixed and interface trap charges in hot-carrier degraded metal oxide s emiconductor held effect transistors (MOSFET's) can be distinguished b y ultraviolet light (lambda=253.7 nm) annealing, and observing the res ultant changes in the gate-to-drain capacitance. Trapped electrons ann eal readily, resulting in large changes in the gate capacitance and th e threshold voltage. This suggests a trap level below the conduction b and edge of SiO2 that is smaller than the photon energy (4.9 eV). In c ontrast, trapped holes and interface traps do not anneal, or anneal in significantly even after prolonged irradiation. This is consistent wit h a much deeper hole trap level in SiO2, generally reported.