Localized Epitaxial Growth of 402 V Breakdown Voltage Quasi-Vertical GaN-on-Si p-n Diode on 200 mm-Diameter Wafers

Localized epitaxy of gallium nitride (GaN) on silicon (Si) wafers is an efficient way to relax elastically the tensile stress generated in the GaN layer after growth, allowing epitaxy of thick layers for the fabrication of vertical power devices operating at high voltage. In this study, a 4.7 mu m-thick GaN layer is grown by metal-organic vapor phase epitaxy on 200 mm-diameter Si wafers for the fabrication of quasi-vertical Schottky and p-n diodes. The uniformity of the doping concentration in the layer is mapped spatially by scanning spreading resistance microscopy, while scanning capacitance microscopy illustrates the differently doped regions in the p-n diode. The net doping concentration is extracted by capacitance-voltage (C-V) measurements and it is found to be about 3 x 1016 cm-3. On a 140 mu m-diameter quasi-vertical p-n diode, destructive breakdown occurs at 402 V, with no periphery protection on the device, demonstrating that localized epitaxy of GaN on Si has great potential for vertical high-power devices. A 5.2 mu m-thick p-n junction has been successfully grown by localized epitaxy of GaN on 200 mm-diameter Si (111) wafers. The drift layer has a uniform doping concentration of about 3 x 1016 cm-3. The fabricated quasi-vertical p-n diode has no periphery protection and destructive breakdown occurs at 402 V, demonstrating the great potential of selective area growth of GaN on Si.image (c) 2024 WILEY-VCH GmbH