Degradation and Recovery of MOS Devices Stressed with FN Gate Current
Degradation and recovery behaviors of n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) and MOS capacitors are discussed based on the empirical power law. Devices with different gate oxide thicknesses, 10 and 33 nm, are stressed with Fowler-Nordheim (FN) gate current and the changes in subthreshold swing (S), drain current (ID), transconductance (Gm), threshold voltage (Vh), interface trap density (Dit) above midgap, interface trapped charge (Qit) above midgap, and effective oxide charge (Q0) are measured during and after stressing. All parameters except Vth and Q0 show recovery after degradation. After some stressing conditions, Vth and Q0 show further degradation. It is found that the changes in parameters, during and after stressing, excluding those in Vth and Q0 can be characterized by power laws. The behaviors of Vth and Q0 are more complex, and the change in Vth is found to be influenced by changes in both Q0 and Qit.
H. Inokawa, E.M. Ajimine, and C.Y. Yang, “Degradation and Recovery of MOS Devices Stressed with FN Gate Current,” Japanese Journal of Applied Physics 30, 1931-1936 (1991).