Sub-1nm EOT WS<sub>2</sub>-FET with I<sub>DS</sub> > 600μA/μm at V<sub>DS</sub>=1V and SS < 70mV/dec at L<sub>G</sub>=40nm
Chin‐Sheng Pang, Peng Wu, Joerg Appenzeller, Zhihong Chen
Abstract
Ultra-scaled WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> field-effect transistors (FETs) with excellent on-state and off-state performance are reported. A record high on-state current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> ) and ultra-low contact resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> ) were achieved in a double-gated FET at a much scaled overdrive voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OV</sub> =V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</sub> -V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ), reaching > 600 (μA/μm) at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> =1V and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OV</sub> =2V with a contact resistance of R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> ~ 500 (Ω*μm). We report statistics of more than 50 FETs with varying channel lengths, showing excellent off-state behaviors with small threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ) variations, near-ideal subthreshold slope (SS), and small drain-induced barrier lowering (DIBL). Various channel thicknesses (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CH</sub> ) ranging from 2.1nm to 7nm were carefully evaluated in terms of short channel effects (SCEs) and on-state current, and a WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> body thickness of 2.1nm (3 layers, the thinnest in our statistics) shows the best performance in both on-state and off-state.