Physical Insights into Flicker Noise in p-GaN Gate AlGaN/GaN HEMTs: A Temperature-Dependent Correlated Carrier-Number and Mobility Fluctuation Model

A temperature-dependent flicker (1/f) noise model is developed for p-GaN gate AlGaN/GaN HEMTs by coupling trap-related fluctuation mechanisms: carrier-number fluctuation (CNF) and carrier-mobility fluctuation (CMF). Based on this, a dimensionless fluctuation-weighting factor is introduced to quantify the relative contribution of CNF and CMF as the two-dimensional electron gas (2DEG) density increases. The model naturally leads to three analytical regimes, corresponding to the low-, moderate-, and strong-2DEG regions. Experimental measurements performed over gate biases of 0.5-4.2 V, temperatures of 300-420 K, and frequencies of 1 Hz-10 kHz show good agreement with the proposed model. The proposed model provides a unified interpretation of bias-, temperature-, and frequency-dependent 1/f noise in p-GaN gate AlGaN/GaN HEMTs and offers a physical basis for trap-related mechanism characterization in normally-off GaN power devices.