Novel Gate-All-Around Metal–Oxide–Semiconductor Field Effect Transistors with Self-Aligned Structure

Abstract

We proposed a new self-aligned gate-all-around metal–oxide–semiconductor field effect transistor (MOSFET) with a wide source/drain region. The device was fabricated by using the concept of the self-aligned double-gate fin-type FETs (FinFETs) with additional processes. The minimum gate length and fin width were 35 and 20 nm, respectively. The gate oxide thickness was 2.4 nm. For the fabricated devices, we confirmed that drain induce barrier lowering (DIBL) and sub-threshold swing (SS) were properly suppressed in spite of the short channel length. We also performed a simulation-based analysis to explore the effects induced by oversized bottom gate in the proposed device structure. If the lateral source/drain doping gradient was not steep, the oversized bottom gate could lead to the enhancement of the gate controllability and the suppression of short channel effects. As a result, the intrinsic gate delay of the proposed devices was improved when the bottom gate was somewhat oversized.