Future Trends in Microelectronics

2.7

Gallium Nitride-Based Lateral and Vertical Nanowire Devices

Y.-W. Jo, D.-H. Son, K.-S. Im and J.-H. Lee

School of Electronics Engineering, Kyungpook National University, 80, Daehak-ro, Buk-gu, Daegu, South Korea

1 Introduction

GaN-based field-effect transistors (FETs) are widely used in power switching and amplifier applications due to the superior material properties of GaN, such as wide bandgap, high breakdown electric field, and high electron saturation velocity, which result in high current density and high breakdown voltage.^{1 2} However, GaN-based devices still suffer from challenges, such as surface and buffer-related trapping effects, that occasionally result in severe current collapse decrease and degradation of the off-state performances. While surface-related problems can be effectively addressed by appropriate surface treatment and passivation techniques,^3–6 trapping in the buffer layer cannot be easily solved because the buffer layer usually contains many defects originating from the heteroepitaxial growth of the GaN layer. Recently, AlGaN-/GaN-based triple-gate fin-shaped field-effect transistors (fin-FETs) have demonstrated superior off-state performance and also suggested a possible avenue for reducing the buffer-related trapping effects.^7–10 Even though the GaN-based gate-all-around (GAA) structure have not been realized with top-down approach thus far due to their complicated fabrication process, the GAA structure seems to exhibit greatly improved on- and ...