Very High Sustainable Forward Current Densities on 4H-SiC p-n Junctions Formed by VLS Localized Epitaxy of Heavily Al-Doped p++ Emitters
This study deals with the electrical characterization of PiN diodes fabricated on a 4°off-axis 4H-SiC n+ substrate with a n- epilayer (1×1016 cm-3 / 10 µm). Optimized p++ epitaxial areas were grown by Vapour-Liquid-Solid (VLS) transport to form p+ emitters localized in etched wells with 1 µm depth. Incorporated Al level in the VLS p++ zones was checked by SIMS (Secondary Ion Mass Spectroscopy), and the doping level was found in the range of 1-3×1020 at.cm-3. Electrical characterizations were performed on these PiN diodes, with 800 nm deposit of aluminium as ohmic contact on p-type SiC. Electrical measurements show a bipolar behaviour, and very high sustainable forward current densities ≥ 3 kA.cm-2, preserving a low leakage current density in reverse bias. These measurements were obtained on structures without any passivation and no edge termination.
Konstantinos Zekentes, Konstantin V. Vasilevskiy and Nikolaos Frangis
S. Sejil et al., "Very High Sustainable Forward Current Densities on 4H-SiC p-n Junctions Formed by VLS Localized Epitaxy of Heavily Al-Doped p++ Emitters", Materials Science Forum, Vol. 897, pp. 63-66, 2017