Low-Temperature Transport Characteristics and Quantum-Confinement Effects in Gate-All-Around Si-Nanowire N-MOSFET

Abstract

Gate-all-around n-MOSFETs with Si-nanowire (~7 nm) as the channel body are fabricated and characterized for their low-temperature behavior (~5 K to 295 K). I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> -V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</sub> characteristics at low V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> (~50 mV) exhibit a decrease in current with decreasing temperature in strong inversion up to about ~200 K. However, at high V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> , drain current reverts to typical temperature behavior, i.e., I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> increases with the reducing temperature due to the increase in phonon-limited mobility (mu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ph</sub> )- It is inferred that, at low V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> the enhancement in mu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ph</sub> at a reduced temperature could be possibly masked by the intersubband scattering on account of subband splitting due to quantum-confinement effects as indicated by subband calculations for nanowire structures.