Gate oxide trap characterization under DC and pulse stress

Gate oxide and interface trap charges are critical parameters for device reliability and their generation and recovery are investigated under AC and DC oxide field stress on n-channel MOSFETs by C-V, I-V, and CP measurements. The interface traps generation is the same under both DC and AC stress but oxide charge trap generation is higher at AC stress than DC stress. The oxide charge and interface trap generation rate is independent of frequency from low to 10 MHz but increase with stress time. The generated interface traps are positioned in the middle of the band gap and oxide traps are negatively charged and located in the upper half of the energy band gap due to the electron injection from the inversion layer. Both interface and oxide trap charges are characterized by high frequency and quasi-static C-V measurement.