Fully Automated RF-Thermal Stress Workbench with S-Parameters Tracking for GaN Reliability Analysis

The rapid development of III-V technologies for telecommunication and radar markets need the meeting of performances (power, frequency) criteria as well as reliability assessment. Nitride HEMT technologies are known to reveal a large variety of failure electrical signatures, and it is also largely accepted that multi-tools (multi physics) approaches is the only suitable way to understand the failure mechanisms and to improve the technologies. Experimental stress workbenches usually allow to track a given number of static/dynamic parameters, but specific characterization are only performed at initial and final steps on the devices. This paper proposes a new approach with S-parameters measurement performed during RF stresses without removing the devices under test (in a thermally controlled oven). Then intermediate knowledge of the electrical (small signal) behavior of the devices can be assessed, and crossed with large-signal and static time-dependent signatures.