1kV AlGaN/GaN power SBDs with reduced on resistances

Abstract

Lateral Schottky Barrier Diodes (SBDs) with reduced on resistances (Ron) and breakdown voltages (Vbd) of higher than 1kV were fabricated on AlGaN/GaN/Si HEMT epi wafers. To improve the forward characteristics of the SBDs, an additional ohmic metal deposition process (2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> ohmic process) has been inserted between the first ohmic metallization process and a Schottky metal deposition process. To minimize the increase of the reverse leakage current, various 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> ohmic metal patterns under the Schottky metal or a patterned Schottky electrode structure have been used to figure out optimum SBD designs. The proposed SBDs have achieved 25~75% lower on resistances at the operating voltages of 1.5~1.8V, and the leakage current increase due to the additional 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> ohmic structures reduced to 1~3 orders of magnitude increase from 5 to 6 order of magnitude increase.