Formation of Structured Low-Ohmic p-Type Contacts on Al-Implanted 4H-SiC by Laser Annealing

In this work, a method is presented to form structured low-ohmic p-type contacts on Al-implanted 4H-SiC by laser annealing. A metal layer sequence for p-type contacts suitable for UV laser treatment was developed. Furthermore, a method to protect thermosensitive layers from damages by laser treatment is presented. By structuring the top metallization layer, it is possible to use the metal stack as a self-aligned mask. That makes it possible to laser the entire surface of the wafer, whereby thermosensitive layers are protected from damages by laser annealing by utilizing the optical properties of the individual metal layers. To evaluate the method, TLM structures were electrically characterized. TLM structures were electrically characterized successfully demonstrating the feasibility of the presented approach.