Impact of HfO₂ Dielectric on DC/RF Characteristics of AlN/GaN/AlGaN/SiC MOSHEMTs

This paper reports the impact of high-K dielectric material HfO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, lateral scaling, oxide thickness (t<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ox</inf>), & gate metals on DC & RF behaviour of GaN-channel MOSHEMT with 100 nm (gate length). A MOSHEMT incorporating R-Gate, AlN barrier, and AlGaN-back barrier, is simulated at 300 K using TCAD tools. GaN channel MOSHEMT with HfO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> as gate oxide tendered a g<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m, peak</inf>) of 449.1 mS/mm, a I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS, peak</inf> of 2.24 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 208 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. Further lowering in t<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ox</inf> leads to the right shift in V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf>, enhancements in g<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m, 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 reduced gate work function(ϕ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf>) offered 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 is observed in V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf>, when the gate work function (ϕ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf>) of gate metal is increased from 4.3 eV (Al) to 5.65 eV (Pt). Reduced L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS (</inf>Source (S) to Gate (G) length) and L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf> (Drain (D) to Gate (G) length) improves the DC/RF performance of GaN Channel MOSHEMT.