Study on Electrical and Temperature Characteristics of β-Ga₂O₃-Based Diodes Controlled by Varying Anode Work Function

This study systematically investigates the effects of anode metals (Ti/Au and Ni/Au) with different work functions on the electrical and temperature characteristics of β-Ga₂O₃-based Schottky barrier diodes (SBDs), junction barrier Schottky diodes (JBSDs) and P-N diodes (PNDs), utilizing Silvaco TCAD simulation software, device fabrication and comparative analysis. From the perspective of transport characteristics, it is observed that the SBD exhibits a lower turn-on voltage and a higher current density. Notably, the V_on of the Ti/Au anode SBD is merely 0.2 V, which is the lowest recorded value in the existing literature. The V_on and current trend of two types of PNDs are nearly consistent, confirming that the contact between Ti/Au or Ni/Au and NiO_x is ohmic. A theoretical derivation reveals the basic principles of the different contact resistances and current variations. With the combination of SBD and PND, the V_on, current density, and variation rate of the JBSD lie between those of the SBD and PND. In terms of temperature characteristics, all diodes can work well at 200 °C, with both current density and V_on showing a decreasing trend as the temperature increases. Among them, the PND with a Ni/Au anode exhibits the best thermal stability, with reductions in V_on and current density of 8.20% and 25.31%, respectively, while the SBD with a Ti/Au anode shows the poorest performance, with reductions of 98.56% and 30.73%. Finally, the reverse breakdown (BV) characteristics of all six devices are tested. The average BV values for the PND with Ti/Au and Ni/Au anodes reach 1575 V and 1550 V, respectively. Moreover, although the V_on of the JBSD decreases to 0.24 V, its average BV is approximately 220 V. This work could provide valuable insights for the future application of β-Ga₂O₃-based diodes in high-power and low-power consumption systems.