Dielectric Engineering to Enhance the Breakdown Voltage of $\boldsymbol{\beta}-\mathbf{G a}_{2} \mathbf{O}_{3}$ MOSFET

The proposed work investigates the impact of high-<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\kappa$</tex> dielectric <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2}$</tex> on the breakdown characteristics of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2} \mathrm{O}_{3}$</tex> MOSFETs. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2}$</tex> helps reduce the electric field peak at the gate edge towards the drain side, owing to it's high dielectric constant, thereby increasing the breakdown voltage up to 1141 V. However, standalone <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2}$</tex> as gate dielectric introduces significant interface states and traps due to lattice mismatch with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2} \mathrm{O}_{3}$</tex>. To mitigate this, a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2} / \text{Al}_{2} \mathrm{O}_{3}$</tex> bilayer gate dielectric is proposed, with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2}$</tex> dielectric is grown over <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Al}_{2} \mathrm{O}_{3}$</tex> layer which lies on the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2} \mathrm{O}_{3}$</tex> channel. The thicknesses of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Al}_{2} \mathrm{O}_{3}$</tex> are optimized to achieve maximum breakdown voltage upto 1136 V. Subsequently, the study examines the role of different dielectric thickness combinations on the drain current and the device threshold voltage. Thus, this study will be instrumental in developing high breakdown voltage <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2} \mathrm{O}_{3}$</tex> MOSFETs by employing high- <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\kappa$</tex> dielectric with optimized thickness.