This study optimizes the CuO_x/Ga₂O₃ heterojunction diodes (HJDs) by tailoring the structural parameters of CuO_x layers. The hole concentration in the sputtered CuO_x was precisely controlled by adjusting the Ar/O₂ gas ratio. Experimental investigations and TCAD simulations were employed to systematically evaluate the impact of the CuO_x layer dimension and hole concentration on the electrical performance of HJDs. The results indicate that increasing the diameter dimension of the CuO_x layer or tuning the hole concentration to optimal values significantly enhances the breakdown voltage (V_B) of single-layer HJDs by mitigating the electric field crowing effects. Additionally, a double-layer CuO_x structure (p⁺ CuO_x/p⁻ CuO_x) was designed and optimized to achieve an ideal balance between the V_B and specific on-resistance (R_on,sp). This double-layer HJD demonstrated a high V_B of 2780 V and a low R_on,sp of 6.46 mΩ·cm², further yielding a power figure of merit of 1.2 GW/cm². These findings present a promising strategy for advancing the performance of Ga₂O₃ devices in power electronics applications.

Gallium nitride high-electron-mobility transistors (GaN HEMTs) are critical for high-power applications like AI power supplies and robotics but face reliability challenges due to increased dynamic ON-resistance (R_{DS_ON}) from electrical and thermomechanical stresses. This paper presents a novel self-calibrating temperature-sensitive electrical parameter (TSEP) model that uses gate leakage current (I_G) to estimate junction temperature with high accuracy, uniquely addressing aging effects overlooked in prior studies. By integrating I_G, aging-induced degradation, and failure-in-time (FIT) models, the approach achieves a junction temperature estimation error of less than 1%. Long-term hard-switching tests confirm its effectiveness, with calibrated R_{DS_ON} measurements enabling precise remaining useful life (RUL) predictions. This methodology significantly improves GaN HEMT reliability assessment, enhancing their performance in resilient power electronics systems.

This study demonstrates the fabrication of high-performance p-Cu₂O/n-β-Ga₂O₃ heterojunction barrier Schottky (JBS) diodes using copper as a low-work-function anode metal. By optimizing the Cu₂O spacing to 4 μm, the device achieves a turn-on voltage of 0.78 V, a breakdown voltage of 1700 V, and a specific on-resistance of 5.91 mΩ·cm², yielding a power figure of merit of 0.49 GW/cm². The JBS diode also exhibits stable electrical characteristics across the temperature range of 300–425 K. Under a 200 V reverse stress for 5000 s, the JBS diode shows only a 4.16% degradation in turn-on voltage and a 1.15-fold increase in dynamic specific on-resistance variation, highlighting its excellent resistance to stress-induced degradation. These results indicate that Cu₂O/Ga₂O₃ JBS diodes are promising candidates for next-generation high-efficiency and high-voltage power electronic applications.