Homoepitaxial GaN terahertz planar Schottky barrier diodes

Abstract In this work, a new type of terahertz Schottky barrier diode (SBD) based on homoepitaxial gallium nitride (GaN) was fabricated for high-power and high-frequency multiplier applications. The measured full width at half maximum of x -ray diffraction peaks for homoepitaxial GaN (002) and (102) plane is only one third of the heteroepitaxial GaN on sapphire substrate. Additionally, the increased electron mobility in both n−/n+ GaN epitaxial layers, induced by improved material quality, can effectively reduce the epitaxial resistance ( R epi ) and the spreading resistance. As a result, the total series resistance of the fabricated GaN SBD is 13.7 Ω, which is only 65% of that of heteroepitaxial GaN on a sapphire substrate. Additionally, the cut-off frequency ( f c ) is improved to 1.61 THz at zero bias voltage and the measured breakdown voltage is 16.17 V at −1 μ A.