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-μm to 11-μm. 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-μm 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.