1200-V/10-A Low Thermal Resistance Ga₂O₃ Schottky Barrier Diode With Composite Terminal Structure and Substrate Thinning

In this work, a superior-performance β-Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub> vertical Schottky barrier diode (SBD) with high breakdown voltage, low thermal resistance, low ON-resistance, high surge current, and high Baliga’s figure of merit (FOM) is achieved by a composite terminal structure of mesa and dual field plate, combined with substrate thinning process. Grinding and polishing are utilized to eliminate the subsurface damage layer, thereby achieving a low ohmic resistance. Benefitting from the thinned substrate with a thickness of 85 μm, the ON-resistance of device with 2 × 2 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup> anode area decreases from 174 to 112 mΩ. As a result, the corresponding forward current increases from 6.04 to 10.1 A at a bias of 2 V, and the surge current increases from 20 to 29 A. More importantly, the thermal resistance of the packaged device significantly reduces from 6.45 to 2.21 K/W, which is comparable to those of commercial SiC SBDs. Besides, a record Baliga’s FOM of 342 MW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup> with a breakdown voltage of over 1200 V is reached among reported β-Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub> SBDs with large anode area (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\ge$</tex-math></inline-formula>1.5 × 1.5 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup>). The results show the broad prospects of Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub> SBD in high-voltage and high-power electronic devices.