Photo-carrier generation as the origin of Fowler-Nordheim-induced substrate hole current in thin oxides

The widely accepted anode-hole injection model assumes that the breakdown o f oxide films during electrical stress is due to backflow of holes created in the anode by hot electrons. This explanation has been supported by the o bservation of a substrate hole current during Fowler-Nordheim (FN) substrat e electron injection in n-type MOSFETs gate. In this paper, we reexamine th e origin of the FN-induced substrate hole current. Based on direct experime nts performed on nMOSFETs, we concluded that not the anode hole injection, but the generation of electron-hole pairs in the substrate by FN-induced ph otons in the gate, is the dominant source of the substrate hole current. Co nsequently, the generally accepted explanation of oxide degradation based o n the anode hole injection model might therefore have to be revised.