NEW OBSERVATION AND THE MODELING OF GATE AND DRAIN CURRENTS IN OFF-STATE P-MOSFETS

The work reports new observations concerning the gate and drain curren ts measured at off-state conditions in buried-type p-channel LDD MOSFE T devices. Detailed investigation of the observed phenomena reveals th at 1) the drain current can be separated into two distinct components: band-to-band tunneling in the gate-to-drain overlap region and collec tion of holes generated via impact ionization by electrons inside the oxide; and 2) the gate current can be separated into two distinct comp onents: the hot electron injection into the oxide and the Fowler-Nordh eim electron tunneling through the oxide. At low negative drain voltag e, the dominant component of the drain current is the hole generation inside the oxide. At high negative drain voltage, the drain current is essentially due to band-to-band tunneling, and it is correlated with the hot-electron injection-induced gate current.