4.15 kV/4.6 mΩ⋅cm² 4H-SiC Epi-Refilled Super-Junction Schottky Diode With Ring Assisted Super-Junction Termination Extension

In this letter, 4H-SiC super-junction (SJ) Schottky diodes (SBDs) with hexagonal cell were fabricated by trench etching and epi-regrowth process. Quasi-selective epi-regrowth in hexagonal trenches and high aspect ratio of 6 for P-pillars without voids were achieved. Furthermore, a termination with field limiting ring assisted super-junction termination extension (RA-SJTE) was proposed and adopted to suppress the high electric field around the device edge. With such a termination, the breakdown voltage (BV) significantly increases from 1530 V to 4150 V (92% of the TCAD simulation value). The specific on-resistance (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {ON,sp}}\text {)}$ </tex-math></inline-formula> of the fabricated device is 4.6 m<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega \cdot $ </tex-math></inline-formula>cm2, demonstrating a performance higher than the one-dimensional limit of 4H-SiC unipolar devices. These results show the promising future of high-performance 4H-SiC SJ device for multi-kilovolts application.