Two-dimensional analytical model for dual-material control-gate tunnel FETs

Abstract

An analytical model for a dual-material control-gate (DMCG) tunnel field effect transistor (TFET) is presented for the first time in this paper, and the influence of the mobile charges on the potential profile is taken into account. On the basis of the potential profile, the lateral electric field is derived and the expression for the drain current is obtained by integrating the band-to-band tunneling (BTBT) generation rate applicable to low-bandgap and high-bandgap materials over the tunneling region. The model also predicts the impacts of the control-gate work function on the potential and drain current. The advantage of this work is that it not only offers physical insight into device physics but also provides the basic designing guideline for DMCG TFETs, enabling the designer to optimize the device in terms of the on-state current, the on–off current ratio, and suppressed ambipolar behavior. Very good agreements for both the potential and drain current are observed between the model calculations and the simulated results.

Analysis of non-uniform hetero-gate-dielectric dual-material control gate TFET for suppressing ambipolar nature and improving radio-frequency performance*

“…Up to now, many techniques have been proposed to improve I on , such as narrow bandgap materials, [7][8][9][10][11] high-k gate dielectric, [12] hetero-junction mechanism, [13,14] and doping-less TFETs, [15] source-side pocket doping, [16] hetero-stacked TFET, [17] heteromaterial gate, [18,19] etc. The I amb can be reduced by using the dual-material control-gate (DMCG) TFETs, [20] charge plasma-based TFETs with gate engineering, [21,22] gate material workfunction engineering, [23] lightly doped drain, [24] and gate-drain underlap structure. [25,26] Moreover, a hetero-gatedielectric (HGD) TFET with a high gate-oxide dielectric near the source side and a low gate-oxide dielectric near the drain side can enhance I on and obtain promising radio frequency performance.…”

Analytical model and simulation‐based analysis of a work function engineered triple metal tunnel field‐effect transistor device showing excellent device performance

“…where, t 0 ¼ t si =2, V FBi is the flat band voltage, C oxi is oxide capacitance per unit area in respective region. The initial solution of ψ Li ðyÞ as obtained following the method reported in [13] is given by the following:…”

“…On the other hand, use of higher work function in auxiliary gate (as compared to work function value of metal used in drain for charge plasma technique) helps to lower off current or ambipolar current. This TM gate structure with different work functions thus helps to improve switching characteristics and I on / I off ratio more than the method discussed in [13]. Moreover, a Al 2 O 3 layer can be built on Si film using atomic layer deposition (ALD) technique which reduces the chance of trap charges interfering at the Si/Al 2 O 3 interface.…”

Analytical model of surface potential profiles and transfer characteristics for hetero stacked tunnel field-effect transistors

“…To increase I on , many different geometries and materials of TFETs have been developed, such as hetero junction TFETs, [6][7][8] L-shaped gate TFETs, 9) gate all-around TFETs, 10) III-V TFETs, [11][12][13] nanowire TFETs, 14) high-κ gate-oxide dielectric TFETs, 15) and multiple-gate TFETs. 16) The use of dual-material controlgate TFETs, 17) doping-less charge plasma TFETs, 18) charge plasma-based TFETs with gate engineering, 19) dielectric and gate material work function engineering, 20) high-bandgap material on the drain side, lightly doped drain, 21) and without gate-drain overlap 22) can overcome the problem of ambipolar behavior. Much research has been carried out to reduce the SS of TFETs.…”