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Title [REGULAR PAPER] Study on the Influence of Drain Voltage on Work Function Variation Characteristics in Tunnel Field-effect Transistor
Authors (Hyun Woo Kim) ; (Jang Hyun Kim)
Page pp.558-564
ISSN 1598-1657
Keywords Tunnel field-effect transistor (TFET); high-κ/metal gate (HKMG); work function variation (WFV); drain bias dependency; band-to-band tunneling
Abstract This paper investigates the influence of drain voltage (VDS) on the work function (WF) variation (WFV) characteristics in the tunnel field-effect transistor (TFET). For sub-45 nm node technology, the high-κ and metal gate (HKMG) have been proposed to improve the TFET’s weakness for the low Ion. However, the metal gate brings WFV in the gate due to various metal particle directions. Based on the technology computer-aided design (TCAD) simulations, the transfer characteristics, channel potential, and charge density are analyzed to confirm the relation between WFV and VDS. From the simulation results, the phenomena that WFV effects get decreased with lower VDS can be described as a channel potential pinning. This pinning is occurred by inversion charges supplied from the drain to the channel. Therefore, when low VDS is applied, the channel potential does not be modulated proportionally to the applied gate voltage (VGS). Then, it induces the limitation of tunneling occurred from the source to the channel resulting in the decrease of WFV in the TFET.