Correlation of on-wafer 400 V dynamic behavior and trap characteristics of GaN-HEMTs

摘要

A method for identifying the critical traps for the dynamic behavior of gallium nitride high electron mobility transistors (GaN-HEMTs) is described. This method provides information on where the critical traps are located in the horizontal direction. At first, the on-wafer 400 V dynamic behavior of a GaN-HEMT was measured. Acceptor-like trap behavior with 0.14 eV activation energy was observed using conductance analysis. Next, trap characterization was achieved using the capacitance and series conductance transients of a comb-style Schottky barrier diode after electrical stress. Several different biases were applied to determine the locations of the detected traps, because depletion area edges can change upon imposition of different biases. Notably, 0.18 eV acceptor-like trap behavior below the Schottky electrode, 0.44 eV donor-like trap behavior in the access region, and 0.5eV acceptor-like trap behavior in access region were observed. By correlating these diode results with HEMT results, it was concluded that the critical trap behavior likely occurs below the gate electrode in HEMT. As a conclusion, the information obtained with this method should provide useful information for the improvement of device processes.