ELECTRICAL INSTABILITY OF ULTRATHIN THERMAL OXIDES ON SILICON

Electrical stress of n-type metal - tunnel oxide - silicon (MTOS) diod es by applying a positive voltage to the metal results in the appearan ce of unstable positive charge in the oxide. This charge is observed b y an increase in the direct tunnel current as well as a negative shift of the capacitance-voltage (C-V) characteristic. Effects similar to t hese have previously been observed for p-type MTOS diodes stressed wit h negative bias. This similarity makes injection of holes a less likel y candidate for controlling the charging profess.