120 GHz Frequency-Doubler Module Based on GaN Schottky Barrier Diode

Area of Science:

• Solid-state device physics
• Terahertz (THz) technology
• Semiconductor materials science

Background:

• Traditional Gallium Arsenide (GaAs)-based frequency multipliers face limitations in breakdown voltage and heat dissipation for high-power THz sources.
• Schottky barrier diodes (SBDs) are crucial components in frequency multipliers, but their performance is often constrained by material properties.

Purpose of the Study:

• To develop a robust Gallium Nitride (GaN) Schottky barrier diode (SBD) chain for high-power terahertz (THz) applications.
• To design and fabricate a 120 GHz frequency-doubler module utilizing the novel GaN SBD chain.
• To evaluate the performance and power handling capabilities of the GaN-based frequency doubler.

Main Methods:

• Fabrication of a GaN SBD chain using an n-/n+-GaN structure.
• Characterization of the GaN SBD chain for breakdown voltage and cut-off frequency.
• Design and assembly of a 120 GHz frequency-doubler module.
• Testing the frequency doubler's output power, continuous wave (CW) performance, and input power endurance.
• Assessment of SBD performance at elevated anode temperatures.

Main Results:

• The fabricated GaN SBD chain achieved a breakdown voltage of 54.9 V at 1 μA and a cut-off frequency of 587.5 GHz at zero bias.
• The 120 GHz frequency-doubler module, driven by 500 mW CW input power, produced an output power of 15.1 mW at 120 GHz.
• The frequency-doubler module demonstrated resilience, enduring an input power of up to 2 W.
• The GaN SBD chain maintained functionality at an elevated anode temperature of 337.2 °C.

Conclusions:

• GaN SBDs offer a promising alternative to GaAs for high-power THz frequency multipliers due to superior breakdown voltage and thermal characteristics.
• The developed GaN SBD chain and 120 GHz frequency doubler show significant potential for advancing solid-state THz source technology.
• The high operating temperature tolerance of the GaN SBD chain further enhances its suitability for demanding THz applications.