High breakdown voltages on pseudo-vertical p–n diodes by selective area growth of GaN on silicon

Selective area growth (SAG) of gallium nitride (GaN) on silicon (Si) wafers efficiently relaxes the tensile stress that is generated in the GaN layer, when the structure is cooled down to room temperature after the growth. Hence, SAG enables the growth of thicker layers that are capable of operating at higher voltages than those grown in 2D layers. In this study, two GaN layers are grown by SAG on 200 mm-diameter Si(111) wafers by metal organic vapor phase epitaxy for the fabrication of pseudo-vertical p–n diodes. During the growth, the SiH4 precursor flow for the first sample was double than that for the second one. The uniformity of the doping concentration of the layers is investigated by scanning spreading resistance microscopy and the p- and n-type doped regions are examined by scanning capacitance microscopy. A low net doping concentration of 1.4 × 1016 cm−3 is extracted from capacitance–voltage measurements and a destructive breakdown occurs at 700 V for a 90 μm-diameter pseudo-vertical p–n diode. These results show the high potential of the SAG of GaN on Si wafers for vertical power devices.