1.6 kV Vertical Ga₂O₃ FinFETs With Source-Connected Field Plates and Normally-off Operation

Abstract

High performance Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> vertical FinFETs with a breakdown voltage of 1.6 kV, a drain current density of 600 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> have been demonstrated in this work. Fin-shaped channels with sub-micron widths lead to a high threshold voltage of 4 V, and also provide strong RESURF effects to reduce the drain leakage current and increase the breakdown voltage. A low leakage current of lower than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is maintained until the hard breakdown of the transistor. In order to sustain high voltage, a source-connected field plate (FP) supported by a dielectric layer is implemented at the outer edge of the gate pad as the edge termination, which enabled a breakdown voltage almost 2 times as high as those without FP. Device simulation shows that the highest electric field peak appears at the FP edge, which suggests further improvement of the breakdown voltage is possible by optimizing the FP design or implementing additional edge terminations.