The design and fabrication of double-metal (DM) Schottky barrier diodes with various Ti/Au area ratios and a polysilicon (poly-Si) guard ring structure are presented. A method that uses ion implantation in a poly-Si film for guard ring fabrication is used to prevent damaging the silicon surface. Experimental results of the Ti/Au DM structure and the relationship between the effective barrier height and the area ratio are presented and discussed. It was found that the effective barrier height of the Schottky barrier diode can be adjusted by changing the ratio of the DM area, which is not possible with a single-metal structure. (C) 2011 Elsevier B.V. All rights reserved.