Improved DC/RF Performance in AlN/GaN/AlGaN/SiC MOSHEMTs With TiO₂ as a Gate Dielectric

This paper explores the effect of high-K oxide material TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, thickness of oxide (t<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ox</inf>), gate metals & lateral scaling on the RF & DC features of AlN/GaN/AlGaN/SiC- MOSHEMT having a gate length of 100 nm. GaN-quantum well MOSHEMT featuring AlGaN-back barrier, AlN barrier, and R-Gate is analyzed using TCAD tool at 300 K. GaN channel MOSHEMT with TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> as gate oxide offered a g<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf>, <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">peak</inf> of 546.6 mS/mm, I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS peak</inf> of 1.64 A/mm, and cut-off frequency f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf> of 190 GHz for oxide thickness t<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ox</inf> = 3nm. A further reduction in t<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ox</inf> causes a right shift in V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf>, improvements in gm<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">peak</inf>, f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf>, and a decrease in I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS peak</inf>. Metals with a lower gate work function (ϕm) yield the optimal I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS peak</inf>. Furthermore, a right shift in V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf> occurs as the gate work function (ϕm) rises from 4.3 eV (Al) to 5.65 eV (Pt). A decrease in L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf> (Source-Gate length) and L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf> (Drain-Gate length) enhances the RF/DC features of the new device.