Characterisation of Polarization Super-Junction Power devices in Gallium Nitride

GaN Polarisation Superjunction (PSJ) technology utilises charge balance concepts using the polarisation effects in GaN, significantly enhancing the blocking voltage of GaN power devices. Due to these advantages, it has become one of the promising candidates for the next generation of GaN Power technology. Further exploring findings of the characterisation of the PSJ power devices are introduced in this thesis. POWDEC.K.K, Japan, is one of the first companies which started to investigate PSJ technology. They have made several new PSJ power devices and presented their electrical performances based on their mature and complete technologies, including GaN wafer epitaxial growth, wafer process fabrication, dicing and packaging. The findings obtained from the POWDEC.K.K PSJ samples include (1) the impacts from the top u-GaN and AlN nucleation layer on the sheet density of 2DEG and 2DHG, (2) the mechanisms of the current saturation of PSJ diodes and (3) gate reliability and leakage performance of PSJ HFETs. Moreover, the performances of the PSJ-on-Si power devices obtained from the fabricated samples in Sheffield are also introduced in this thesis