The Development of a New Ion Versus Log(Ig) Plot to Characterize Depletion-Mode High Electron Mobility Transistors with the Insertion of a Very Thin Evaporated Al Layer to AlGaN/GaN High Electron Mobility Transistors as an Example

Abstract

For depletion-mode high electron mobility transistors (HEMTs), the on current (Ion) and the gate leakage current (Ig) alone will not be a good criterion to judge the quality of depletion-mode HEMTs. In this paper, we would like to propose the application of an Ion vs. log Ig plot to characterize depletion-mode HEMTs. Previously, it was proposed the gate leakage current of AlGaN/GaN HEMTs can be reduced by the insertion of a very thin evaporated Al in the Au/Ni metal gate. We will use this as an example to demonstrate the usefulness of the Ion vs. log Ig plot by showing that slowly evaporated Al gate does bring significant improvement.