The Leakage Current of the Schottky Contact on the Mesa Edge of AlGaN/GaN Heterostructure

A test structure, which is called the ridge-furrow structure, is used to evaluate the leakage current of the Schottky contact on the mesa edge of an AlGaN/GaN heterostructure. The mesa edge leakage currents were measured at different temperatures from 300 to 500 K and analyzed. The conduction-band-edge energy distribution at the mesa edge is simulated by the Integrated Systems Engineering Technology Computer-Aided Design. Based on the simulation results, the electric field strength can be obtained as a function of reverse bias voltage. The mesa edge leakage current is found to agree with the predicted characteristics, which is based on the Frenkel-Poole emission model. Therefore, we believe that the Frenkel-Poole emission dominates the mesa edge leakage at temperatures between 300 and 500 K.