  A new compact modeling approach is presented which describes the full
current-voltage (I-V) characteristic of high-performance (aggressively
scaled-down) tunneling field-effect-transistors (TFETs) based on homojunction
direct-bandgap semiconductors. The model is based on an analytic description of
two key features, which capture the main physical phenomena related to TFETs:
1) the potential profile from source to channel, and 2) the elliptic curvature
of the complex bands in the bandgap region. It is proposed to use 1D Poisson's
equations in the source and the channel to describe the potential profile in
homojunction TFETs. This allows to quantify the impact of source/drain doping
on device performance, an aspect usually ignored in TFET modeling but highly
relevant in ultra-scaled devices. The compact model is validated by comparison
with state-of-the-art quantum transport simulations using a 3D full band
atomistic approach based on Non-Equilibrium Green's Functions (NEGF). It is
shown that the model reproduces with good accuracy the data obtained from the
simulations in all regions of operation: the on/off states and the n/p branches
of conduction. This approach allows calculation of energy-dependent band-toband
tunneling currents in TFETs, a feature that allows gaining deep insights into
the underlying device physics. The simplicity and accuracy of the approach
provides a powerful tool to explore in a quantitatively manner how a wide
variety of parameters (material-, size- and/or geometrydependent) impact the
TFET performance under any bias conditions. The proposed model presents thus a
practical complement to computationally expensive simulations such as the 3D
NEGF approach.
