Impact of Charge Carrier Trapping on GaN-HEMT Characteristics at Cryogenic Temperatures

This paper presents an investigation of the static and dynamic on-resistance RDS,on using a fully automated, modular measurement setup, which enables the characterization of commercially available Gallium-Nitridehigh- electron mobility transistors at cryogenic temperatures (77K). The circuit is based on an extended modified double pulse test, enabling the characterization in an application-oriented setup over a wide temperature range while minimizing self-heating effects. The focus is on the investigation of charge-carrier trapping in terms of dynamic on-resistance dRDS,on at cryogenic temperature. The presented setup enables systematic investigation of these effects, with distinguishable trapping sources. Measurements of the static on-resistance RDS,on show a significant decrease due to the increased electron mobility at cryogenic temperatures. Results of dynamic on-resistance dRDS,on analysis show a much reduced degradation of dRDS,on compared to measurements at room temperature under soft-switching and hardswitching, as well as a negligible effect after the application of a drain-voltage-bias.