Effects of CF₄ plasma treatment on electrostatic discharge performance of AlGaN/GaN schottky barrier diodes

In this research, CF₄ plasma treatment was performed to improve the reliability of the Schottky barrier diode. The investigation of the Schottky barrier diode focused on improving in the leakage current, breakdown voltage and electrostatic discharge (ESD) characteristics of the device. The CF₄ plasma treatment was performed using CF₄ (30 sccm) gas under a 50 W RF power and a 10 mTorr working pressure on the surface of an AlGaN layer for 30 seconds. The current of the device was decreased when the plasma treatments were used. The forward current was decreased 7-12 times, and the leakage current was decreased 95-1100 times, as well. However, the breakdown voltage and the ESD characteristics of the devices were improved because of the decrease in the leakage current. The measurements of ESD were conducted using human body model (HBM), and the ESD characteristics of the device were improved by plasma treatments. With increasing area of the Schottky diode, the ESD characteristics were dramatically improved. Therefore, the CF₄ plasma treatment in the area of the AlGaN/GaN SBD can be concluded to have improved the robustness of the device (resistance to an ESD) by decreasing the leakage current.