Papers by Keyword: Turn-On

Abstract: The Army Research Laboratory has collaborated with Cree, Inc. and Silicon Power Corp. to develop 9 kV-blocking, 1.0 cm² Super-GTOs. In this study, several 1.0 cm² GTOs were individually switched up to 6.0 kA in a low-inductance, high dI/dt (2.1 kA/µs) circuit to evaluate turn-on delay and optimize the gate control. Turn-on delay was evaluated relative to gate drive current, and the delay was reduced by 1.1 µs when gate amplitude was increased from 1 A to 8 A. Increasing gate current delivered to each GTO also successfully reduced variation in turn-on delay from device to device by at least 50%, and mitigated mismatch in turn-on between pairs of GTOs switched in parallel. As silicon carbide material processing and device development continue to evolve, the ultimate solution will be to reduce remaining material defects and to control minority carrier diffusion length through more uniform doping across the wafer. These steps will enable modules of parallel GTOs to perform at maximum capability.

Abstract: SiC power device is expected to have high breakdown voltage with low on resistance, which cannot be attainable for conventional Si device. This study evaluates the switching performance of high voltage SiC MOSFETs with comparing to that of conventional Si power MOSFET having equivalent breakdown voltage. To this end, turn-on and turn-off switching operation of MOSFETs are assessed with resistive load for same conduction current density. Though the on resistance of SiC MOSFETs are quite lower than Si MOSFET, especially for trench gate type. But, SiC MOSFETs have larger terminal capacitance. Therefore, SiC MOSFETs show slower switching speed than Si MOSFETs for same current density condition.

Abstract: We report on the development of the first 1 cm x 1 cm SiC Thyristor chip capable of blocking 5 kV. This demonstrates the present quality of the SiC substrate and epitaxial material. A forward drop of 4.1 V at 100 A and 25°C has been measured. The turn-on delay is found to be a strong function of the gate current. At a gate current of 0.5 A, a turn-on delay of 250 ns is observed for an anode to cathode current of 200 A. The turn-on delay reduces to 72 ns for an IG = 1.5 A. The turn-on rise time is a strong function of the anode to cathode voltage, VAK. At VAK =230 V, the turn-on rise-time is 300 ns for IAK =200 A. The rise-time reduces to 26 ns for VAK = 500 V.