Degradation analysis of 0.1 μm InP HEMTs using low frequency noise characterization

Low frequency noise technique was introduced to characterize the gate and drain noise spectra on 0.1 μm InP HEMTs before and after degradation (subjected to elevated temperature lifetest at T_junction of 240 °C for 936 hours). It has been found that the gate current noise on the degraded devices increases significantly and exhibits a Lorentzian peak around 15 KHz. The low frequency noise results indicate that the Schottky junction is the primary degradation origin, which is consistent with the electrical results - showing the forward and reverse Schottky junction degradation. Gate current low frequency noise spectra suggest that there are possible interface states and bulk defects generated in the degraded Schottky junction - this was further substantiated with a scanning transmission electron microscope. The results from this study shows that low frequency noise characterization provides a sensitive means to identify the degradation origin and Schottky junction attributes of a degraded InP HEMT.