A link between noise parameters and light exposure in GaAs pHEMT’s

• DC and microwave characterization of an advanced GaAs pHEMT.
• Investigation of transistor performance under optical illumination.
• Scattering and noise parameter measurements.

This work presents an experimental investigation and relevant discussion of the link existing between noise parameters and light exposure of GaAs pseudomorphic HEMT’s at microwave frequencies. A 100 μm gate width AlGaAs/InGaAs/GaAs heterostructure device has been illuminated with CW visible laser light (650 nm) and a systematic analysis has been performed by examining the device behavior under controlled bias current conditions. Significant effects have been brought to evidence in the 2–26 GHz noise parameters Fmin, Γopt and Rn measured in the different conditions. A clear correlation has been found between the level of degradation of the noise parameter behavior and the light exposure.