Investigation on Diffferent Buffer to Supress the RF-Loss in AlGaN/GaN-on-Si HEMTs

An research on High Electron Mobility Transistors (HEMTs) fabricate on different type buffer layers including Al
_x
Ga
_1-x
N stacked buffer and AlGaN/GaN superlattice buffer has been carefully studied. The research including structure analysis via transmission electron microscope (TEM), material investigation via X-ray diffractometer (XRD) and Raman spectrum, the defect quantification by atomic force microscope (AFM) and etch pit density (EPD) test, DC characteristics measurement and RF characteristics measurement. We provide lots of evidence to ensure the better buffer layer type which may attribute to better electrical characteristics for less defect such as dislocation and interface stress.