Ultra-Low Subthreshold Swing in Gated MIS(p) Tunnel Diodes With Engineered Oxide Local Thinning Layers

Abstract

Listen

Translate article

In this article, oxide local thinning (OLT) effects on the performance of a gated metal–insulator–semiconductor tunnel diode (MIS TD) with a p-type substrate were demonstrated through the fabrication of well-defined OLT regions at the gate and the drain. Without soft breakdown treatment of the oxide layer as reported before, the designed OLT patterns give rise to such devices to be of particular use. Specifically, sub-60 mV/decade subthreshold swing (SS) in the transfer characteristics was achieved with OLT regions at the device gate, while the operating voltage, as well as SS, could be further reduced with those at the drain. Moreover, by adjusting the number and area of OLT regions that are evenly distributed within the device, SS could be possibly optimized to a much lower value, e.g., 8.4 mV/decade, over three current decades. The enhanced lateral transport efficiency of minority carriers from the gate to the drain, which leads to the ultra-low SS, is attributed to the OLT region as an extra energy source under negative bias with its effectiveness depending on the area and thicknesses of both the relatively thick and thin oxides. The roles of these physical parameters were investigated using 2-D TCAD simulation and evidenced by experimental results.