Sharp-Switching Devices with Positive Feedback Mechanisms Based on Silicon-On-Insulator Substrate

In this work, we demonstrate Z
²
-FET (zero subthreshold swing and zero impact ionization FET) and UJ-FET (unijunction FET) on silicon-on-insulator substrate utilizing a CMOS-compatible process. Attributed to novel positive feedback mechanisms, the devices can break the subthreshold swing (SS) limitation in conventional MOSFET and exhibit sharp-switching characteristics. Based on the positive feedback between carrier flow and band modulation, the fabricated Z
²
-FET has been demonstrated with SS of 14.2 mV/dec and I
ON
/I
OFF
ratio of 1.5×10
⁷
. Based on the positive feedback between junction voltage and carrier injection, the fabricated UJ-FET has been demonstrated with SS of 1.5 mV/dec and I
ON
/I
OFF
ratio of 3.4×10
⁷
.