Low specific ON-resistance and high Figure-of-merit AlGaN/GaN HEMTs on Si substrate with non-gold metal stacks

Abstract

GaN High-Electron-Mobility transistors (HEMTs) on Si substrate is emerging as the most suitable choice for commercialization due to its low cost and the availability of larger size even up to GaN on 200-mm diameter Si(1 11) substrate [1-3]. Most of the high-power devices on Si (111) have achieved attractive device performances using conventional III-V process. In order to utilize the existing 200-mm diameter Si fabrication line, CMOS-compatible non-gold ohmic contacts with low contact resistance R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> are necessary. For high-power switching application point of view, researchers have demonstrated GaN Metal-Insulator-Semicondcutor HEMTs (MISHEMTs) on Si fabricated with non-gold metal stack. The non-gold ohmic metal stacks on undoped AlGaN/GaN heterstuctures are suffering from high R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> values. Recently, we have demonstrated sub-micron gate GaN HEMTs with low contact resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ) of <;0.24 Ω-mm and smooth surface morphology using non-gold metal stack. So far, there are no reports on the dynamic specific ON-resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS[ON]</sub> ) and OFF-state breakdown voltage (BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gd</sub> ) of AlGaN/GaN HEMTs on Si fabricated using non-gold ohmic and Schottky contacts with. In this study, we report for the first time the BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gd</sub> and dynamic R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ds[ON]</sub> of AlGaN/GaN HEMTs on Si fabricated using non-gold metal stacks.