Abstract
In this work, device parameters for GaN vertical trench MOSFETs have been investigated systematically to further improve the device characteristics. The n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> GaN drift layer, the p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> GaN layer and the trench gate are designed and optimized systematically using Silvaco ATLAS 2-D simulation, in order to get the best trade-off between VBR and specific on-resistance R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> . Three-terminal breakdown curves, the electron concentration, current density and electric field strength distributions have been presented to analyze the breakdown characteristics. The correlations between different parameters and different initial conditions are considered, and the eight parameters are optimized comprehensively. After the final optimization, record high FOM of 4.8 GW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BR</sub> of 2783 V, average electric field E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">drift</sub> of 1.98 MV/cm and a low R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> of 1.6 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> are obtained for drift layer thickness of 14 μm. The product of the thickness L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> and doping density N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> of p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> GaN layer can determine the breakdown mechanism, and punch through mechanism would occur when Lp ·N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> is lower than a certain value. The results indicate there exists large optimization room for fabricated GaN vertical trench MOSFETs, and the device characteristics can be further improved through the methodology in this paper for high power and high voltage applications.
Highlights
GaN-based devices are considered to be candidates for power electronic applications due to wide bandgap, high breakdown field strength, high electron mobility and high 2DEG density
GaN vertical trench MOSFETs with a 4 μm drift layer based on the silicon substrate were fabricated, obtaining a breakdown voltage of 520 V, specific onresistance of 5 m ·cm2 and figure of merit (FOM) of 0.0541 GW/cm2 [14], [15]
The key parameters of GaN vertical trench MOSFETs have not been fully investigated until now, which is very important for achieving high breakdown voltage, low specific on-resistance and high FOM
Summary
GaN-based devices are considered to be candidates for power electronic applications due to wide bandgap, high breakdown field strength, high electron mobility and high 2DEG density. S. Liu et al.: Comprehensive Design of Device Parameters for GaN Vertical Trench MOSFETs doping density of p+ GaN layer (Lp · Np) can determine the breakdown mechanism. GaN vertical trench MOSFETs with a 4 μm drift layer based on the silicon substrate were fabricated, obtaining a breakdown voltage of 520 V, specific onresistance of 5 m ·cm2 and FOM of 0.0541 GW/cm2 [14], [15].
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.
