Scaling perspective for III-V broken gap nanowire TFETs: An atomistic study using a fast tight-binding mode-space NEGF model

Abstract

We report an in-depth atomistic study of the scaling potential of III-V GAA nanowire heterojunction TFET using an innovative tight-binding mode space (MS) technique with large speedup (up to 250×) while keeping good accuracy (error < 1%). It is shown that both n- and pTFET performances are best above 20 nm gate length for a cross-section of 5.5 nm in the [111] crystal orientation. At Vdd = 0.3 V and Ioff = 50 pA/μm, the on-current (Ion) and energy-delay product (ETP) gain over a Si NW GAA MOSFET are 58× and 56× respectively. In a beyond 5 nm node low power ITRS 2.0 horizontal GAA design rule however, where the gate length is restricted to 12 nm, a [100] orientation is best but features up to 3× Ion and 2.4× ETP degradation vs. the 20 nm TFET GAA design.