Study of Gallium Nitride CAVET for Power Electronics and RF Application

Download or read book Study of Gallium Nitride CAVET for Power Electronics and RF Application written by Saptarshi Mandal and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium Nitride-based (GaN-based) devices for power electronics have gained considerable momentum in recent years. Any improvement in conventional silicon-based (Si-based) devices is now incremental. The figure-of-merit for GaN is significantly higher than for Si due to GaN’s wide band-gap and high mobility, which result in high breakdown field and low on-resistance, respectively. Commercial GaN power devices are based on a lateral device topology: namely AlGaN/GaN high-electron mobility transistors (HEMTs). However, HEMTs exhibit well-known dispersion effects that lead to current collapse, increasing the dynamic ON resistance. The breakdown voltage in lateral HEMTs scale with gate-to-drain distance, which necessitates the lateral scaling up of devices to support high breakdown. Vertical topology has inherent advantages due to a buried electric field which enables dispersion-free operation and allows for vertical scaling. The present work addresses the device design, fabrication, and characterization of current-aperture vertical-electron transistors (CAVETs) for power switching application. A study of ion-implanted current-blocking layer (CBL) is used to demonstrate the potential to achieve high breakdown voltage. CAVETs with gate dielectrics show a premature breakdown of 60V due to gate dielectric failure. When the dielectric was replaced by a p-n junction, the breakdown voltage was improved to 500V by using a multiple energy-implantation scheme for the CBL. Thermal analysis of CAVETs was performed, and extracted device-thermal resistance was compared with lateral HEMTs grown on multiple substrates. GaN vertical diodes with avalanche capability were also fabricated and analyzed as potential candidates for transit-time diodes. Finally, design modifications were provided as future work to utilize the CAVET structures in RF power amplifiers.