Experimental and Numerical Investigation on the Effects of the Stress of SiN Passivation on AlGaN/GaN Heterostructures and Their Surface

In this work, plasma-enhanced chemical vapor deposition (PECVD) silicon nitride (SiN) passivation layers with different chemistries and tensile/ compressive stress levels are investigated on Al₀.₂₅Ga₀.₇₅N/GaN heterostructures. The impact of the SiN-induced stress on the two-dimensional electron gas (2DEG) properties was evaluated using Hall measurements to extract the carrier concentration (nₛ) and mobility (µ) before and after each PECVD process. In parallel, a physics-based numerical model was developed using Synopsys Sentaurus TCAD to simulate the influence of SiN passivation on the 2DEG carrier concentration. Simulation results are benchmarked against experimental data.