Development of a Device for On-Die Double-Pulse Testing and Measurement of Dynamic On-Resistance of GaN HEMTs

On-die testing can accelerate development of semiconductor devices, but poses certain challenges related to high frequency and high current switching. This paper describes design and development of a tester for double-pulse switching test and measurement of dynamic on-state resistance of unpackaged High-ElectronMobility Transistors (GaN HEMTs). The tester is capable of switching an inductive load at drain-to-source voltage up to 400 V and drain current up to 10 A. Design challenges resulting from specific properties of GaN HEMTs and on-die measurement are explained, and solutions are proposed. Essential parts of the developed device are described, including low inductance gate-driver and measurement methods. Modified drain voltage clamping circuit for accurate on-state drain voltage measurement is described. The tester is constructed as a printed circuit board, integrated into a probe station. Voltage and current waveforms are measured with oscilloscope and used to calculate the on-resistance. Results of a reference measurement with commercially available packaged transistors are presented. Waveforms measured on experimental unpackaged normally-off GaN HEMT samples are also presented and discussed. The proposed tester device proved to be capable of performing the dynamic on-resistance measurement with satisfactory results.