Enhancing subthreshold slope and ON-current in a simple iTFET with overlapping gate on source-contact, drain Schottky contact, and intrinsic SiGe-pocket

Abstract

In this paper, we present a new novel simple iTFET with overlapping gate on source-contact (SGO), Drain Schottky Contact, and intrinsic SiGe pocket (Pocket-SGO iTFET). The aim is to achieve steep subthreshold swing (S.S) and high I_ON current. By optimizing the gate and source-contact overlap, the tunneling efficiency is significantly enhanced, while the ambipolar effect is suppressed. Additionally, using a Schottky contact at the drain/source, instead of ion implantation drain/source, reduces leakage current and thermal budget. Moreover, the tunneling region is replaced by an intrinsic SiGe pocket posing a narrower bandgap, which increases the probability of band-to-band tunneling and enhances the I_ON current. Our simulations are based on the feasibility of the actual process, thorough Sentaurus TCAD simulations demonstrate that the Pocket-SGO iTFET exhibits an average and minimum subthreshold swing of S.S_avg = 16.2 mV/Dec and S.S_min = 4.62 mV/Dec, respectively. At V_D = 0.2 V, the I_ON current is 1.81 \(\times\) 10^–6 A/μm, and the I_ON/I_OFF ratio is 1.34 \(\times\) 10⁹. The Pocket-SGO iTFET design shows great potential for ultra-low-power devices that are required for the Internet of Things (IoT) and AI applications.