۱- Introduction

۲- Device structure

۳- Analytical model

۴- Simulation results

۵- Conclusion

References

Abstract

Wide bandgap (WBG) semiconductor devices represent an attractive developing technology for power applications that is recently gaining commercial ground. GaN has advantages as one of the top contenders with high bandgap, high mobility, high saturation velocity, and high breakdown voltage. GaN enhancement-mode devices are favored over depletion-mode devices for power electronics applications and are only recently becoming commercially available. The enhancement-mode device investigated in this work is a GaN-gate injection transistor (GIT) in which the normally-off operation is achieved with an additional p-doped gate. This paper presents current-voltage (I-V) characteristics of GaN-GIT device using a physics based compact model as well as TCAD (Technology Computer-Aided Design) numerical simulation to predict and model the device behavior of the GIT. This paper presents a comparison of the TCAD simulation results with a compact model intended for low frequency applications in power electronics in the KHz to MHz range.

Introduction

During the past few years, researchers have focused their attention on wide bandgap (WBG) materials for power electronics applications. Extensive research on GaN devices during the past decade has demonstrated the realization of these devices with superior on-resistance, higher breakdown voltage and smaller device sizes compared to conventional Si power devices. GaN is particularly coveted for its high breakdown voltage, high mobility and high saturation velocity as illustrated in Table 1 [1]. Most of the GaN based transistors reported to date are typically lateral heterojunction fieldeffect transistor (HFET) or high electron mobility transistor (HEMT) due to the availability of two-dimensional electron gas (2DEG) created by spontaneous and piezoelectric polarization of AlGaN/GaN heterojunction. The mechanical stress results in piezoelectric polarization which occurs in the same direction as the tensile strain formed by AlGaN. Due to the presence of native 2DEG channel the device is inherently depletion-mode or normally-on which is undesirable for power electronic applications. An emerging device technology that achieves enhancement-mode operation of AlGaN/GaN HEMT incorporates a p-doped GaN layer beneath the gate electrode. This type of configuration is termed as the gate injection transistor (GIT) [2-3]. This device structure has several advantages over the other enhancement-mode GaN HEMT structures due to its low on-resistance and high current density.