Superior electrostatic control in uniform monolayer MoS₂ scaled transistors via in-situ surface smoothening

Abstract

Transistors with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2\mathrm{D}$</tex> materials hold the promise for extreme gate length scaling enabled by the very thin channel, hence ultimate electrostatic control. However, to date, little has been demonstrated as channel defectivity impacts SS and variability. Here we report the demonstration of short channel transistors with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}_{\text{OFf}}\leq 10\text{pA}/\mu \mathrm{m}$</tex> for ultra-scaled devices, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}_{\text{ON}}/\mathrm{I}_{\text{OFF}} &gt;10^{7}$</tex> , low median <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SS}_{\min}$</tex> of 68mV/dec, and low VT variation with Pelgrom slope ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{A}_{\text{VT}}$</tex> , a variability index) of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.2\text{mV}-\mu \mathrm{m}$</tex> . This is similar to sub-10nm fin width <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{W}_{\text{fin}})$</tex> Si FinFETs <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\text{EOT} =0.8\text{nm})$</tex> with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{A}_{\text{VT}}=2.5\text{mV}-\mu \mathrm{m}$</tex> . The statistical analysis has been performed on more than 15000 devices, with smooth monolayer Mos2 deposited via MOCVD and an in-situ surface smoothening method, which precisely controls monolayer thickness and uniformity.