Epitaxial growth of a low-doped 4H-SiC layer on a micropipe stop layer

In this study we investigated a two-epilayer system, which consists of a high-doped micropipe stop (MS) layer and a low-doped active layer, for high-voltage 4H-SiC devices. Epitaxial growth of the 4H-SiC layers was performed using SiH4 and C3H8 as the source gases: For MS layers, a high probability of micropipe dissociation is maintained for a wide range of n-type doping from mid 10(15) to low 10(19) cm(-3) at a relatively low C/Si ratio of the source gases. Growth of a low-doped active layer on a MS layer is possible at a relatively high C/Si ratio without coalescence of elementary screw dislocations that are generated by the dissociation of micropipes in the MS layer. A large Ni/4H-SiC Schottky barrier diode (SBD) with a diameter of 11.2 mm (similar to1 cm(2)) was fabricated using a MS layer and a low-doped active layer. The leakage current of the SBD at 1 kV was 14 mA, and the on-state voltage at 100 A was 2.8 V.