Zr-Based Contacts to n-Type AlN With Improved Performance for Power and High-Temperature Electronics

This work reports improved ohmic contacts on n-type AlN using a Zr/Al/Mo/Au metal stack with contact resistivities of ~10-3Ω⋅cm2at 25°C and ~10-5Ω⋅cm2at 500°C, which are over one and two orders of magnitude lower than Ti-based contacts, respectively. Temperature-dependent current-voltage characteristics reveal thermionic-field emission-dominated transport at the Zr/AlN interface, leading to improved conductivity and ohmic behavior above 400°C. Record-low specific on-resistance (Ron,sp) is achieved in AlN Schottky barrier diodes using Zr-based cathode compared to previously reported values at comparable breakdown voltages. The devices reveal 10× enhanced Baliga Figure of Merit at 300°C and 500°C due to significantly loweredRon,sp2.