Design and simulation of AlN-based vertical Schottky barrier diodes

The key parameters of vertical AlN Schottky barrier diodes (SBDs) with variable drift layer thickness (DLT) and drift layer concentration (DLC) are investigated. The specific on-resistance (R_on,sp) decreased to 0.5 mΩ·cm² and the breakdown voltage (V_BR) decreased from 3.4 kV to 1.1 kV by changing the DLC from 10¹⁵ cm^-3 to 3×10¹⁶ cm^-3. The V_BR increases from 1.5 kV to 3.4 kV and the R_on,sp also increases to 12.64 mΩ·cm² by increasing DLT from 4-μ to 11-μ. The V_BR enhancement results from the increase of depletion region extension. The Baliga's figure of merit (BFOM) of 3.8 GW/cm² was obtained in the structure of 11-μ DLT and 10¹⁶ cm^-3 DLC without FP. When DLT or DLC is variable, the consideration of the value of BFOM is essential. In this paper, we also present the vertical AlN SBD with a field plate (FP), which decreases the crowding of electric field in electrode edge. All the key parameters were optimized by simulating based on Silvaco-ATLAS.