Abstract
A new AlGaN/AlN/GaN high electron mobility transistor (HEMT) structureusing a compositionally step-graded AlGaN barrier layer is grown onsapphire by metalorganic chemical vapour deposition (MOCVD). Thestructure demonstrates significant enhancement of two-dimensionalelectron gas (2DEG) mobility and smooth surface morphology comparedwith the conventional HEMT structure with high Al composition AlGaNbarrier. The high 2DEG mobility of 1806 cm2/Vs at roomtemperature and low rms surface roughness of 0.220 nm for a scan areaof 5 μm×5 μm are attributed to the improvement ofinterfacial and crystal quality by employing the step-graded barrier toaccommodate the large lattice mismatch stress. The 2DEG sheet density isindependent of the measurement temperature, showing the excellent 2DEGconfinement of the step-graded structure. A low average sheet resistanceof 314.5 Ω/square, with a good resistance uniformity of 0.68%,is also obtained across the 50 mm epilayer wafer. HEMT devices aresuccessfully fabricated using this material structure, which exhibits amaximum extrinsic transconductance of 218 mS/mm and a maximum draincurrent density of 800 mA/mm.
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.
