High-Quality Interface in ${\rm Al}_{2}{\rm O}_{3}/{\rm GaN}/{\rm GaN}/{\rm AlGaN}/{\rm GaN}$ MIS Structures With In Situ Pre-Gate Plasma Nitridation

Abstract

We report an in situ low-damage pre-gate treatment technology in an atomic layer deposition (ALD) system prior to the ALD- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm Al}_{2}{\rm O}_{3}$</tex></formula> deposition, to realize high-quality <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm Al}_{2}{\rm O}_{3}/{\rm III}\hbox{-}{\rm nitride}$</tex></formula> (III-N) interface. The technology effectively removes the poor quality native oxide on the III-N surface while forming an ultrathin monocrystal-like nitridation interlayer (NIL) between <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm Al}_{2}{\rm O}_{3}$</tex></formula> and III-N surface. With the pre-gate treatment technology, high-performance <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm Al}_{2}{\rm O}_{3}({\rm NIL})/{\rm GaN}/{\rm AlGaN}/{\rm GaN}$</tex></formula> metal–insulator–semiconductor high-electron-mobility transistors are demonstrated, exhibiting well-behaved electrical characteristics including suppressed gate leakage current, a small subthreshold slope of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\sim}{\rm 64}~{\rm mV/dec}$</tex></formula> , and a small hysteresis of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\sim}{\rm 0.09}~{\rm V}$</tex></formula> .