Gate Injection Transistor (GIT)—A Normally-Off AlGaN/GaN Power Transistor Using Conductivity Modulation

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We have developed a normally-off GaN-based transistor using conductivity modulation, which we call a gate injection transistor (GIT). This new device principle utilizes hole-injection from the p-AlGaN to the AlGaN/GaN heterojunction, which simultaneously increases the electron density in the channel, resulting in a dramatic increase of the drain current owing to the conductivity modulation. The fabricated GIT exhibits a threshold voltage of 1.0 V with a maximum drain current of 200 mA/mm, in which a forward gate voltage of up to 6 V can be applied. The obtained specific <emphasis emphasistype="smcaps">ON</emphasis>-state resistance (<formula formulatype="inline"><tex>$R_{ \scriptstyle{\rm ON} } \cdot A$</tex></formula>) and the <emphasis emphasistype="smcaps">OFF</emphasis>-state breakdown voltage (<formula formulatype="inline"><tex>$\hbox{BV}_{\rm ds}$</tex></formula>) are 2.6 <formula formulatype="inline"><tex>$\hbox{m}\Omega\cdot \hbox{cm}^{2}$</tex></formula> and 800 V, respectively. The developed GIT is advantageous for power switching applications. </para>