N. Noda, K. Horio
Shibaura Institute of Technology, Japan
pp. 274 - 277
Keywords: GaN HEMT, current collapse, field plate, deep acceptor
Two-dimensional transient analysis of field-plate AlGaN/GaN HEMTs is performed in which a deep acceptor is considered in a semi-insulating buffer layer, and quasi-pulsed current-voltage curves are derived from them. It is studied how the existence of the deep acceptor and the field plate affects buffer-related drain lag, gate lag and current collapse. It is shown that the drain lag is reduced by introducing a field plate, because electron injection into the buffer layer is weakened by it, and the trapping effects by the deep acceptor are reduced. It is also shown that the current collapse and gate lag are reduced in the field-plate structure. The dependence on SiN passivation layer thickness is also studied, suggesting that there is an optimum thickness of SiN layer to minimize the buffer-related current collapse and drain lag in AlGaN/GaN HEMTs.