Improvement of AlGaN/GaN HEMTs Linearity Using Etched-Fin Gate Structure for Ka Band Applications

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Devices

Background:

• High electron mobility transistors (HEMTs) are crucial for high-frequency applications.
• Device linearity is a key performance metric for power amplifiers.
• AlGaN/GaN HEMTs offer superior performance characteristics for millimeter-wave frequencies.

Purpose of the Study:

• To investigate the impact of etched-fin gate structures on AlGaN/GaN HEMT linearity.
• To optimize device linearity for Ka-band wireless applications.
• To identify the optimal number of etched fins for improved performance.

Main Methods:

• Fabrication of AlGaN/GaN HEMTs with varying numbers of etched-fin gate structures (planar, one, four, nine).
• Characterization of device linearity using extrinsic transconductance (Gm), output third order intercept point (OIP3), and third-order intermodulation output power (IMD3).
• Analysis of device performance at Ka-band frequencies (30 GHz).

Main Results:

• The four-etched-fin gate AlGaN/GaN HEMT demonstrated optimized linearity.
• A 7 dB improvement in IMD3 was achieved at 30 GHz for the 4 × 50 μm HEMT.
• The maximum OIP3 reached 36.43 dBm with the four-etched-fin device.

Conclusions:

• Etched-fin gate structures significantly enhance the linearity of AlGaN/GaN HEMTs.
• The four-etched-fin design offers the best trade-off for linearity in Ka-band applications.
• These optimized HEMTs show high potential for advanced wireless power amplifier components.