The electron–hole bilayer tunnel FET

Abstract

We propose a novel tunnel field-effect transistor (TFET) concept called the electron–hole bilayer TFET (EHBTFET). This device exploits the carrier tunneling through a bias-induced electron–hole bilayer in order to achieve improved switching and higher drive currents when compared to a lateral p–i–n junction TFET. The device principle and performances are studied by 2D numerical simulations. Output and transfer characteristics, as well as the impact of back gate bias, silicon thickness and gate length on the device behavior are evaluated. Device performances are compared for Si and Ge implementations. Nearly ideal average subthreshold slope (SSAVG∼10mV/dec over 7 decades of current) and ION/IOFF>108 at VD=VG=0.5V are obtained, due to the OFF–ON binary transition which leads to the abrupt onset of the band-to-band tunneling inside the semiconductor channel. Remarkably, for Ge EHBTFETs the ION (∼11μA/μm at VDD=0.5V) is 10× larger than in Ge tunnel FETs and 380× larger than in Si EHBTFETs.