Low <i>Q<sub>C</sub>V<sub>F</sub> </i> 20 A/1.4 kV <i>β</i>-Ga₂O₃ Vertical Trench High-k RESURF Schottky Barrier Diode With Turn-On Voltage of 0.5 V
Saurav Roy, Benjamin Kostroun, Yizheng Liu, Jacqueline Cooke, Arkka Bhattacharyya, Carl Peterson, Berardi Sensale‐Rodriguez, Sriram Krishnamoorthy
Abstract
We present a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 Trench Schottky Barrier Diode (SBD) featuring a high-permittivity (high-k) dielectric RESURF and an atomic layer-deposited (ALD) Ru anode contact to engineer the trade-off between forward voltage drop and reverse leakage current. We created <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~\mu {m}$ </tex-math></inline-formula> deep trenches on the lightly doped <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 drift layer and deposited a high-permittivity BaTiO3 as the RESURF dielectric. By encircling the trenches with the anode metal, the electric field at the metal/semiconductor junction is effectively reduced. Consequently, we were able to utilize a low work-function metal like Ru without inducing a significant increase in reverse leakage current. The high-k RESURF trench SBD, spanning an area of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${200}\times {200}~\mu {m}^{{2}}$ </tex-math></inline-formula>, demonstrated a low turn-on voltage of 0.5 V and a reverse breakdown voltage exceeding 3 kV, with a leakage current density of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2~\textit {mA}/\textit {cm}^{{2}}$ </tex-math></inline-formula> at 3kV. The larger area <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${1}\times {1}~\textit {mm}^{{2}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${2}\times {2}~\textit {mm}^{{2}}$ </tex-math></inline-formula> devices exhibited breakdown voltages of 1.74kV and 1.42kV, respectively, while accommodating maximum pulsed forward currents of 6A and 20A, respectively. The devices presented here exhibit very low product of stored charge and forward voltage drop (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{C}V_{F}$ </tex-math></inline-formula>) for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gt {1}$ </tex-math></inline-formula> A, 1 kV device, indicating promising switching and conduction loss trade-off for multi-kilovolt class applications.