Study On Simulation Of 4h-SiC Trenched Junction Barrier Schottky(TJBS) Diodes

As an outstanding material in the third generation of semiconductor family, Silicon Carbide(Si C) can work in high temperature, high-power and high-frequency occasions because of its superior electrical properties. As the high withstand voltage, high-speed and large current power diode, JBS is regard as one of the most developing and promising diodes.This paper presents an improved structure-trenched junction barrier schottky(TJBS) diodes to make up the disadvantage of common JBS, conduct the study on simulation of it with the help of numberical simulation software Sentaurus-TCAD. The common JBS, conditioned to the depth of ion implantation, the protection of schottky barrier from adjacent pn junctions is limited. When the trench is introduced, the depth of pn junction becomes adjustable, because of deeper pn junction, the schottky barrier shield effect is reinforced, so the leakage current of device decrease sharply.Firstly, the TJBS cell is studied, using the parameters of 1200 V devices: the thickness of epilayer is 10?m, and its doping concentration is 5×15/cm3. Two cell structures are First-implant structure(TJBS_A) and First-trench structure(TJBS_B), after the comparison, we find that the latter's performance is better because of the deeper implant depth under the same implant energy and the simpler process. Then aimed at the TJBS_B structure, the influence of implant depth and trench depth, implant width and trench width,deviation of the alignment on their forward and reverse characteristicsarealldiscussed, show that this structure can reduce reverse leakage current only when the implant width is wider than the trench width, underthe condition, the deeper the trench depth, the lower the leakage current. The influence of deviation of the alignment is small in the allowable range(under 1?m). Under the same implant depth and line width ratio, the TJBS's protection to schottky area is stronger, with better forward performance at the same breakdown condition compared to planar JBS. Then the full structure of TJBS with field limiting ring termination that introduced B trench is studied, then the occasion that trenched on the termination is discussed, which shows that its best performance appears when the main junction and termination are both trenched.