600 V/7 A Large-Size RESURF β-Ga₂O₃ Schottky Barrier Diode With High-Temperature Storage Test

Abstract

A new design concept to improve the blocking capability and reliability is proposed and verified by simulations and experiments. Based on the concept, the reduced surface field (RESURF) <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 Schottky barrier diode (SBD) is fabricated. Its electrical characteristics are investigated and the thermal stability is evaluated by the long-time high-temperature storage (HTS) test from 400 to 450 K. The RESURF structure is achieved by the oxidation region and SiO2 trench termination. First, the oxidation region is formed by thermal oxidation treatment (TOT) to reduce the surface electron concentration and passivate the oxygen-vacancy type interface states. It not only reduces surface electric field peak ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\text {max}}{)}$ </tex-math></inline-formula> and optimizes the vertical electric field profile, but also improves reliability. Second, the SiO2 trench further reduces the charges to decrease the surface <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E} _{\text {max}}$ </tex-math></inline-formula> . The large-size RESURF SBD exhibits a withstand voltage of 600 V with the reverse leakage current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {R}}{)}$ </tex-math></inline-formula> of less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10 ~\mu \text{A}$ </tex-math></inline-formula> , as well as a forward current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {F}}{)}$ </tex-math></inline-formula> of 7 A. After the HTS test up to 450 K, the forward <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}-{V}$ </tex-math></inline-formula> curves exhibit a less than 2% positive shift with almost constant ON-resistance and turn-on voltage; the withstand voltage is still up to 600 V without a sharp increase in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {R}}$ </tex-math></inline-formula> ; and the fluctuations of extracted reverse recovery time/charge ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T}_{\text {rr}}/{Q}_{\text {rr}}{)}$ </tex-math></inline-formula> are less than 5%. The fabricated large-size RESURF <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 SBD achieves good compressive performance and thermal stability, showing the great potential in high power applications under high-temperature condition.