Advanced measurement methods for high-power gallium nitride high electron mobility transistors

The testing and modeling of semiconductor devices are the foundation of circuit design. The issue of high-power device testing urgently needs to be solved as the power level of the devices under test (DUTs) increases. This work proposes advanced measurement methods based on three aspects of "measuring capability, security, and stability" with a focus on the features of high output power, easy self-oscillation in mismatch tests, and safety risk in the measurement system of high-power transistors. In this paper, the wideband limiter and bias filter network are innovatively introduced to improve the stability and security of the measurement circuit. Meanwhile, the output signal of the DUT is suggested to be measured using a spectrum analyzer before the test to avoid damage to the circuit caused by the possible self-oscillation of the transistor. Moreover, an efficient test system of current parameters and S-parameters is developed, with coaxial fixtures offered to boost the test power capacity and cascade bridges adapted to satisfy the pulse operating conditions. Finally, based on the improved test methods, a gallium nitride high electron mobility transistor (GaN HEMT) with a gate width of 400 × 32 μm and a power density of roughly 10 W/mm was tested. A relatively complete I-V curve and a S-parameter curve were obtained, demonstrating the effectiveness and applicability of the improved methods.