Impact of Gamma Radiation on Dynamic R_DSON Characteristics in AlGaN/GaN Power HEMTs

Area of Science:

• Power Electronics
• Semiconductor Devices
• Radiation Effects

Background:

• Gallium Nitride (GaN) High-Electron-Mobility Transistors (HEMTs) are advanced devices for power electronics, offering superior performance over silicon in demanding applications.
• GaN HEMTs are crucial for radiation-intensive environments like space converters, requiring high frequency and voltage capabilities.
• A key reliability concern for GaN HEMTs in power switching converters is dynamic on-state resistance (R_{ON_dyn}).

Purpose of the Study:

• To investigate the drain-to-source on-resistance (R_DSON) of two commercial GaN HEMT structures under ⁶⁰Co gamma radiation.
• To analyze the impact of different bias conditions during irradiation on device parameters and trapping effects.
• To understand how gamma radiation influences dynamic resistance and trapping behavior in switching GaN HEMTs.

Main Methods:

• Irradiation of two distinct commercial power GaN HEMT structures using ⁶⁰Co gamma rays.
• Application of various bias conditions during irradiation and static measurements (threshold voltage, leakage currents).
• Measurement of dynamic resistance (R_{ON_dyn}) to assess device trapping under switching conditions.

Main Results:

• Device performance under gamma radiation is highly dependent on the specific HEMT structure and applied bias conditions.
• A free current collapse GaN HEMT structure demonstrated significant stability up to 3.7 Mrad(Si).
• The other tested structure exhibited substantial degradation in measured parameters due to radiation-induced or enhanced trapping effects.

Conclusions:

• Gamma radiation significantly impacts GaN HEMT reliability, primarily through trapping effects.
• Device design, specifically current collapse features, plays a critical role in radiation tolerance.
• Understanding these trapping mechanisms is essential for developing robust GaN HEMTs for radiation-heavy applications.