Improving Transport Properties of GaN-Based HEMT on Si (111) by Controlling SiH4 Flow Rate of the SiNx Nano-Mask

Abstract

The AlGaN/AlN/GaN high electron mobility transistor structures were grown on a Si (111) substrate by metalorganic chemical vapor deposition in combination with the insertion of a SiNx nano-mask into the low-temperature GaN buffer layer. Herein, the impact of SiH4 flow rate on two-dimensional electron gas (2DEG) properties was comprehensively investigated, where an increase in SiH4 flow rate resulted in a decrease in edge-type threading dislocation density during coalescence process and an improvement of 2DEG electronic properties. The study also reveals that controlling the SiH4 flow rate of the SiNx nano-mask grown at low temperatures in a short time is an effective strategy to overcome the surface desorption issue that causes surface roughness degradation. The highest electron mobility of 1970 cm2/V·s and sheet carrier concentration of 6.42 × 1012 cm−2 can be achieved via an optimized SiH4 flow rate of 50 sccm.

The Effect of Heavy Fe-Doping on 3D Growth Mode and Fe Diffusion in GaN for High Power HEMT Application

“…A similar result was also observed in Sample B ; the total TD densities also reduced from 2.81 × 10 9 to 2.32 × 10 9 cm −2 due to the transition of 2D-3D-2D growth by Fe nano-mask. Current investigation is similar to our previous publication, which reports the application of a SiN nano-mask to decrease dislocation density [6].…”

“…Both the mosaic model and Kaganer model could be used to determine the dislocation density [29][30][31][32]. In Table 1, the FWHM of GaN (002) and ( 102) planes (i.e., β (002) and β (102) ) can be analyzed with the mosaic model to identify the type of dislocations (screw or edge-type) by the following formulas [6]: The screw-type TD densities (D screw ) and edge-type TD densities (D edge ) were calculated by β (002) , β (102) , and Burger vector length (b screw and b edge ). The FWHM of GaN (002) plane corresponding to the screw-type TD densities showed similar results on these three samples.…”

“…There are several methods to achieve 3D growth, such as the epitaxial lateral overgrowth (ELOG) technique [ 5 ] either with nano-mask [ 6 , 7 , 8 ] or without nano-mask [ 9 ]. In our previous study, the bulk TD density was mitigated by the insertion of SiN x nano-mask in the low temperature (LT) buffer [ 6 ].…”

“…There are several methods to achieve 3D growth, such as the epitaxial lateral overgrowth (ELOG) technique [ 5 ] either with nano-mask [ 6 , 7 , 8 ] or without nano-mask [ 9 ]. In our previous study, the bulk TD density was mitigated by the insertion of SiN x nano-mask in the low temperature (LT) buffer [ 6 ]. In the case of n -type defect compensation, the most common approach is using carbon or iron doping to form deep acceptors [ 10 , 11 , 12 , 13 , 14 ].…”

High Hole Concentration and Diffusion Suppression of Heavily Mg-Doped p-GaN for Application in Enhanced-Mode GaN HEMT

“…However, the p-GaN/AlN-IL structure displayed a similar H concentration to p-GaN/AlGaN, which could not expound the higher hole concentration and activation efficiency with AlN-IL. Therefore, these two structures were measured by the HRXRD rocking curves for the FWHM of GaN (002) and (102) planes to calculate the threading dislocation densities (TDDs) [ 38 ]. The GaN (002)/(102) planes of 678/1024 arcsecs without AlN-IL, respectively, correspond to the screw/edge-type TDDs of 9.24 × 10 8 and 3.13 × 10 9 cm −2 .…”