Steep Switching Characteristics of L-Shaped Tunnel FET With Doping Engineering

Abstract

In this work, a L-shaped tunnel FET (TFET), which has the dominant tunneling current in the normal direction to the gate, is introduced with the doping engineering and its electrical characteristics are analyzed using TCAD device simulations. The proposed L-shaped TFET has the pocket doping (p + -doping for ntype operations) underlying the gate, which can suppress the corner tunneling generated near the source edge by the electricfield crowding. Thus, the on/off transition is significantly improved since the corner tunneling is the main cause of the degradation of the switching characteristics. To maximize the performance enhancement, the concentration of the pocket doping (NPOC) is optimized. As a result, the averaged subthreshold swing (SSAVE) gets reduced from 60 to 26 mV/dec and the on-current (ION) becomes ~ 2.0 times increased as compared to the conventional Lshaped TFETs. Moreover, it is confirmed that the pocket doping effectively suppresses the corner tunneling without the on-current reduction even in the extremely scaled gate length (LG) device.

Sensitivity, linearity, and noise evaluation of L‐shaped dielectrically modulated label free tunnel field‐effect transistor biosensor

“…The larger on-state current directly correlates to enhanced sensitivity in a dielectric-modulated L-shaped TFET (DM-LTFET). [20][21][22] In this particular study, the depth of the cavity was sufficient, ensuring stronger gate control ability. The study explores and discusses the impact of various topologies, including tunneling length and modifications in the nonlocal BTBT (band-to-band tunneling) mechanism.…”

“…The recombination effects were addressed by the implementation of the Shockley-Read-Hall recombination model, accompanied by the application of the Fermi-Dirac distribution statistics. 26,27 In order to ensure consistency for both the proposed and used models, the simulation results are calibrated based on reference [20]. Please refer to the curve depicted in Figure 1B.…”

“…20 The HfO2 layer is formed on both the horizontal and vertical arms using the atomic layer deposition process. 20 Subsequently, metal is deposited on the vertical oxide layer to act as gate 1, and a similar procedure is applied for gate 2. Finally, an 18 nm cavity is generated by etching out the oxide beneath the metal, in the vertical and horizontal arms, facilitate the capture of target biomolecule.…”

Physics based analysis of a high-performance dual line tunneling TFET with reduced corner effects

“…The proposed device shows an improvement in the ON-state current (I ON ) and SS avg due to enhanced tunneling area with the help of L-shaped pocket and extended back gate. In addition to this, the presence of L-shaped pocket mitigates the corner effects caused due to the electric filed crowding across the source channel interface [25,26]. In this paper, the various design parameters like pocket thickness, and doping concentration are optimized by analyzing the DC performance of the proposed device.…”

An accurate analytical surface potential model of heterojunction tunnel FET

“…The fabricated III-V heterostructure TFET (H-TFET) with a lateral tunneling junction has demonstrated excellent performance with sub-thermal operation, reaching down to 48 mV/decade, and a high current of 10.6 µA/µm at drain-to-source bias of 0.3 V. [4] The TCAD predicted III-V H-TFET with a trench gate and InGaAs pocket structure achieves simultaneously 921 µA/µm on-current and average subthreshold swing of 4.9 mV/dec. [5] Despite significant experimental and finite-element simulation efforts, [4][5][6][7][8][9][10][11][12] an accurate analytical model of the TFET is urgent and indispensable to provide further insight into the physics of the device and to accelerate the process of device and circuit designs. Furthermore, the potential model is the cornerstone of the capacitance and current models, [13,14] which thus needs to be modeled more accurately.…”