AlGaN/GaN-based SBDs grown on silicon substrates with trenched n+-GaN cap layer and local passivation layer to improve BFOM and dynamic properties

• The trenched n+-GaN cap layer doubles the 2DEG density, reducing specific ON-resistance to ~2.4 mΩ·cm². • The Si3N4 passivation layer suppresses surface defects from dry etching, reducing leakage current to ~8×10⁻⁵ A·cm⁻² and achieving a breakdown voltage of 876 V. • The proposed structure achieves a Baliga's figure of merit (BFOM) of ~319 MW·cm⁻², a significant improvement. • The Si3N4 layer also suppresses electron capture and transport, improving dynamic ON-resistance characteristics.