| Summary: | GaN devices are nowadays attracting global attention due to their outstanding performance in high voltage, high frequency, and anti-radiation ability. Research on total ionizing dose and annealing effects on E-mode GaN Cascode devices has been carried out. The Cascode device consists of a low-voltage MOSFET and a high-voltage depletion-mode GaN MISHEMT. Cascode devices of both conventional processed MOSFET and radiation-hardened MOSFET devices are fabricated to observe the TID effects. Experiment results indicate that, for the Cascode device with conventional processed MOSFET, the <i>V</i><sub>TH</sub> shifts to negative values at 100 krad(Si). For the Cascode device with radiation-hardened MOSFET, the <i>V</i><sub>TH</sub> shifts by −0.5 V at 100 krad(Si), while shifts to negative values are 500 krad(Si). The annealing process, after the TID experiment, shows that it can release trapped charges and help <i>V</i><sub>TH</sub> recover. On one hand, the <i>V</i><sub>TH</sub> shift and recover trends are similar to those of a single MOSFET device, suggesting that the MOSFET is the vulnerable part in the Cascode which determines the anti-TID ability of the device. On the other hand, the <i>V</i><sub>TH</sub> shift amount of the Cascode device is much larger than that of a previously reported p-GaN HEMT device, indicating that GaN material shows a better anti-TID ability than Si.
|
|---|