The reverse and forward gate-diode drain current in ultra-thin LDD nMOSFET´s

The reverse and forward gated-diode drain (GDD) current in LDD NMOSFET with 1.4nm gate oxide have been studied. It is found that the reverse GDD current increases sharply with decreasing the gate voltage V_G when the channel is in the accumulation region and the forward GDD current increases sharply with increasing V_G when the channel is in the inversion region. These phenomena are different from that of the device with the thick gate oxide. In the accumulation region, the reverse GDD current is very large because of the large gate-induced drain tunneling (GIDL) current induced by the thin gate oxide. The forward V_G effectively make the drain PN junction forward biased due to thin gate oxide when the channel is in the inversion region in the case of the forward GDD current. Then the large PN junction current is generated and this leads to the forward GDD current increases quickly with increasing V_G.