Gate length scaling effect on high-electron mobility transistors devices using AlGaN/GaN and AlInN/AlN/GaN...

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• Gallium Nitride (GaN) based High-Electron-Mobility Transistors (HEMTs) are critical for high-frequency and high-power applications.
• AlGaN/GaN HEMTs face challenges with transconductance roll-off, limiting performance at scaled gate lengths.

Purpose of the Study:

• To compare the performance of AlInN/AlN/GaN HEMTs with traditional AlGaN/GaN HEMTs.
• To investigate the impact of heterostructure material on device characteristics, particularly transconductance roll-off.
• To assess the potential for achieving high current density, transconductance, and operating frequencies.

Main Methods:

• Fabrication and characterization of AlInN/AlN/GaN and AlGaN/GaN High-Electron-Mobility Transistors (HEMTs).
• Electrical measurements to determine current density, transconductance, and frequency response (ft, fmax).
• Analysis of transconductance roll-off behavior as a function of gate length scaling.

Main Results:

• AlInN/AlN/GaN HEMT demonstrated significantly higher current density (1558 mA/mm) and transconductance (330 mS/mm) compared to AlGaN/GaN HEMT.
• Extrinsic cutoff frequency (ft) of 82 GHz and maximum oscillation frequency (fmax) of 70 GHz were achieved for AlInN/AlN/GaN HEMT.
• Transconductance roll-off was significantly reduced in AlInN/AlN/GaN HEMT, indicating improved performance stability.

Conclusions:

• The AlInN/AlN/GaN heterostructure offers superior device performance, including higher current and transconductance, compared to AlGaN/GaN.
• The improved transconductance behavior suggests that high carrier density and lattice-matched epitaxy are key for advanced HEMT designs.
• These findings highlight the potential of AlInN/AlN/GaN HEMTs for next-generation high-power and high-frequency electronics, especially with aggressive scaling.