Substrate hole current and oxide breakdown

It is known that when an n‐channel metal‐oxide‐semiconductor field‐effect transistor is biased with a high positive gate voltage, a hole current appears in the substrate cathode. Recent experiments indicate that the holes are generated within the oxide. We show that this hole generation mechanism is linked to oxide time‐dependent breakdown. When the hole fluence reaches a certain critical value, breakdown occurs. This is in agreement with a hole‐trapping‐induced breakdown model. For very thin oxides the hole generation rate can become so low that the substrate hole current is dominated by the tunneling of valence‐band electrons which is not expected to contribute to oxide breakdown. A different mechanism of hole generation such as hot‐hole tunneling from the anode may be responsible for oxide breakdown in the important case of low gate voltage (<6 V).