Cost-Effective Test Setup for Measuring Threshold Voltage Shift of GaN-HEMTs under Long-Term Drain-Voltage Stress

GaN-HEMTs offer low on-resistances and low capacitances, making them attractive candidates for high efficient power electronic converters. In this field of application, the normally-off transistor is the preferred structure but can exhibit threshold voltage instability problems. Undesired threshold-shifts can lead to increased switching losses or unintended turn-on events. Typically, the dedicated and expensive semiconductor device characterization equipment is unavailable in application-oriented power electronics labs. Therefore, this paper proposes a cost-effective test setup based on standard laboratory equipment to measure the threshold voltage shift due to static long-term drain voltage stress. The test procedure alternates between stress periods and short measurement pulses, during which the transfer characteristic is recorded.