Effects of $\hbox{N}_{2}$ Plasma Pretreatment on the SiN Passivation of AlGaN/GaN HEMT

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The impact of <emphasis emphasistype="italic">in situ</emphasis> low-power <formula formulatype="inline"><tex> $\hbox{N}_{2}$</tex></formula> plasma pretreatment, prior to silicon-nitride (SiN) deposition, was investigated in AlGaN/GaN high-electron mobility transistors (HEMTs). These studies reveal that the use of <formula formulatype="inline"><tex>$\hbox{N}_{2}$</tex></formula> plasma in HEMT passivation reduces current-collapse and gate-lag effects. Such treatment is also beneficial to improve gate leakage, and from RF measurements, no degradation of <formula formulatype="inline"><tex>$f_{\max}$</tex></formula> was observed. These beneficial effects of the <formula formulatype="inline"><tex>$\hbox{N}_{2}$</tex></formula> plasma pretreatment seem to be due to a significant reduction in interface charge density, as shown in this letter using GaN MIS devices, where a decrease of 60% was observed. </para>