Doping-less tunnel field-effect transistors by compact Si drain frame/Si0.6Ge0.4-channel/Ge source

Abstract

Tunnel field-effect transistors (TFETs) have attracted immense interest as a promising alternative to complementary metal-oxide semiconductors for low-power-consumption applications. However, conventional TFETs introduce both random dopant fluctuations and ambipolar current issues at negative gate voltages for sub-6-nm technology nodes. In this study, we address the performance of charge plasma-driven doping-less TFETs, including sub-3-nm thick compact drain (CD) geometry/SiGe-channel/Ge source layers for suitable bandgap engineering. An ultrathin CD frame and heteromaterials are adopted for use as channels/sources to improve the ambipolarity and ON-state features, respectively. Simulation demonstrates a clear reduction in the ambipolar current from 3.3 x 10(-14) to 3.0 x 10(-17) A at gate (V-G)/drain (V-D) voltages of -1.5/1.0 V and an enhancement in the ON-current from 2.0 x 10(-5) to 8.6 x 10(-5) A at V-G = 1.5 and V-D = 1.0 V, compared with conventional TFETs. In addition, diverse fabrication-friendly metals applicable to industry fieldwork sites are tested to determine how the metal work functions influence the outputs. The use of Ti/W/Ni as the drain/channel/source materials, respectively, yields an enhanced ambipolar current of 1.2 x 10(-20) A and an ON-current of 3.9 x 10(-5) A.