Modelling and characterization of GaN-HEMT devices with respect to effects of charge carrier trapping

• Applicants: Professor Dr.-Ing. Marc Hiller; Privatdozent Dr.-Ing. Martin Sack
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Electrical Energy Systems, Power Management, Power Electronics, Electrical Machines and Drives
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 462921712

The key objective of the proposed project is to enhance a recently developed new method or combined device characterization and modelling of power semiconductors in order to cover all relevant device properties of GaN-HEMTs. This includes an experimental device characterization of GaN based power semiconductors in a broad frequency range up to 500 MHz as well as the development of a device model suitable for extensive circuit simulations and circuit design. The main work packages comprise small-signal RF-measurements in the frequency domain as well as time-domain measurements, serving both as data base for the subsequent modelling process.The project is based on measurement and modelling techniques, which have been developed and set up in previous work of the applicants. The work packages described in this proposal will continue this work with a special focus on GaN power semiconductors and the related trapping effects of charge carriers. This comprises measurements that will allow a characterization of trapping-related relaxation times in the time domain and of the trapping-related variation of the amplification factor of the transistors in the frequency domain, and as well of other effects such as the temperature-dependent variation of the on-state resistance Rds,on.The following goals will be addressed in the proposed project:- Implementation of a modified version of the already existing test setup of GaN HEMTs for small-signal RF-measurements with improved measurement accuracy,- Design and implementation of a setup enabling time-domain measurements of voltages and currents at the DUT in pulsed mode for different load conditions,- Measurements with both test setups in the frequency and time domain to obtain the raw data for subsequent modelling,- Development of a model for circuit simulation covering both the small-signal RF-properties of the device and additionally effects of charge carrier trapping andtemperature,- Validation of the model and application to the design of a fast switching power device,- Application of the switch model based on the above mentioned methods for the design of an assembly with parallel connected GaN HEMTs.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2312: Energy Efficient Power Electronics "GaNius"