Abstract
The role of low-resistivity substrate on vertical leakage current (VLC) of AlGaN/GaN-on-Si epitaxial layers has been investigated. AlGaN/GaN high-electron-mobility transistors (HEMTs) grown on both p-type and n-type Si substrates with low resistivity are applied to analyze the vertical leakage mechanisms. The activation energy (Ea) for p-type case is higher than that for n-type at 0–600 V obtained by temperature-dependent current-voltage measurements. An additional depletion region in the region of 0–400 V forms at the AlN/p-Si interface but not for AlN/n-Si. That depletion region leads to a decrease of electron injection and hence effectively reduces the VLC. While in the region of 400–600 V, the electron injection from p-Si substrate increases quickly compared to n-Si substrate, due to the occurrence of impact ionization in the p-Si substrate depletion region. The comparative results indicate that the doping type of low-resistivity substrate plays a key role for VLC.
Highlights
Gallium-nitride (GaN)-based devices have recently attracted increasing attention for optoelectronic applications, such as light-emitting diodes (LED) [1], laser diodes (LD) [2], ultraviolet (UV)detectors [3,4], and power electronic devices [5]
Several challenges remain that need to be resolved regarding Si substrate, in particular, stronger charge trapping effects caused by high-resistivity Si [7], degradation due to electron injection from Si [8], and breakdown related to the inversion channel at the AlN/Si interface in GaN-based high-electron-mobility transistors (HEMTs) [9]
We investigated the impact of different Si substrate types with low resistivity on the vertical leakage current (VLC) in AlGaN/GaN epitaxial layers
Summary
Gallium-nitride (GaN)-based devices have recently attracted increasing attention for optoelectronic applications, such as light-emitting diodes (LED) [1], laser diodes (LD) [2], ultraviolet (UV)detectors [3,4], and power electronic devices [5]. High-electron-mobility transistors (HEMTs) of GaN-based power devices on silicon (Si) substrates are considered promising candidates for high-power electronic applications because of their superior properties, such as high breakdown voltage, high current driving capability, and high thermal stability [6]. Several challenges remain that need to be resolved regarding Si substrate, in particular, stronger charge trapping effects caused by high-resistivity Si [7], degradation due to electron injection from Si [8], and breakdown related to the inversion channel at the AlN/Si interface in GaN-based HEMTs [9]. GaN-on-Si lateral devices is thought to be limited by top-to-bottom vertical leakage current (VLC) in the end [10]. Understanding the vertical leakage mechanisms related to Si substrate is an essential step toward potential power device applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
