Study and Fabrication of High Power GaN p-i-n Diodes Grown on Sapphire

• Main Authors: Chang, Yung Fu, 張永富
• Other Authors: Wu, Meng Chyi
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/69880560261085606591

博士 === 國立清華大學 === 電子工程研究所 === 103 === In this study, the Gallium Nitride (GaN) p-i-n diodes grown on pattern sapphire substrates by MOCVD have been fabricated to study the electrical characteristics of the GaN p-i-n diodes. To be a great high power device, the reverse breakdown characteristics of GaN p-i-n diodes are dominated by the capabilities of defect suppression at reverse bias; at the same time, the forward series resistances of GaN p-i-n diodes must be reduced for low power dissipation at forward bias. In this study, firstly, the edge termination effects of the GaN p-i-n diodes including the damages resulted from ICP etching and electric field distribution were inhibited by using two-step mesa structure and suitable process parameters, and these fabricated devices exhibited great performances. After the suitable process flow has been confirmed, the GaN p-i-n diodes with ultra-low i- layer concentration have been fabricated. Finally, the results of the devices with ultra-low i- layer concentration and two-step mesa structures show the high BFOM values and the high breakdown voltage values, respectively. The device with the highest BFOM is very close to the dash line for SiC-limit. The fabricated devices with suitable process parameters and low i- layer concentrations are greater than the previous reports of the GaN p-i-n diodes grown on sapphire substrates.