US Patent 9576899 Electrical fuse with high off resistance

Electrical fuses and methods for forming an electrical fuse. A semiconductor substrate is implanted to define a modified region in the semiconductor substrate. Trenches that surround the modified region and that penetrate into the semiconductor substrate to a depth greater than a depth of the modified region are formed in the modified region so as to define a fuse link of the electrical fuse. The substrate is removed from beneath the fuse link with a selective etching process that removes the semiconductor substrate with a first etch rate that is higher than a second etch rate of the modified region.