Analysis of backside-electrode and gate-field-plate effects on buffer-related current collapse in AlGaN/GaN high electron mobility transistors

Two-dimensional transient analysis of gate-field-plate AlGaN/GaN high electron mobility transistors with a backside electrode is performed by considering a deep donor and a deep acceptor in a buffer layer. Effects of introducing a field plate and a backside electrode on buffer-related lag and current collapse are studied. It is shown that gate field plate introduction is effective in reducing lag and current collapse when the acceptor density in the buffer layer is high. On the other hand, backside electrode introduction is shown to be effective in reducing drain lag and current collapse, particularly when the acceptor density in the buffer layer is relatively low, because the fixed potential at the backside electrode reduces electron injection into the buffer layer and the resulting trapping effects.