Improvement of electrostatic discharge characteristics of InGaN/GaN MQWs light-emitting diodes by inserting an n~+ -InGaN electron injection layer and a p-InGaN/GaN hole injection layer

摘要

To improve the electrostatic discharge properties of InGaN/GaN LEDs, an n~+-InGaN electron injection layer and a p-InGaN/GaN hole injection layer were inserted beneath and above the InGaN/GaN MQWs. The influences of activated donor concentration in n~+-InGaN and acceptor concentration in p-InGaN/GaN and on the depletion width and the internal capacitance of GaN-based n~+-P LED have been investigated. Our research results indicated that the capacitance of GaN-based n~+-P LED is mainly determined by the depletion width which is dependent on the activated acceptor concentration N_A in the p-InGaN/GaN hole injection layer. The relationship between the internal capacitance of InGaN-LEDs and the electrostatic discharge (ESD) properties was also investigated. It was found that the LEDs with large internal capacitance were more resistant to external ESD impulses. With optimized LED structures with n~+-InGaN layer and a p-InGaN/GaN SLs, the HBM-ESD pass yield at -1500 V reached 95%, much higher than the value of 15% in reference samples without inserting layers above.