Multilevel Antifuse Cells with Programmable Contact in Pure 90 nm Logic Process

A multilevel oxide antifuse cell with programmable contact, fully compatible with a standard complementary metal--oxide--semiconductor (CMOS) logic process, is firstly presented for logic nonvolatile memory applications. A four-state antifuse cell has a stable read window and a very small cell size of 0.097 \mbox{$\mu$m} 2 /bit. By adopting the multiple stages in oxide breakdown, four states of read current level have been successfully demonstrated on this cell fabricated by a standard 90 nm CMOS logic process. A fast programming speed of 10 \mbox{$\mu$}s can be obtained using a low programming voltage of less than 4 V. With excellent technology scalability and adaptability, this multilevel antifuse cell provides a very promising solution for programmable logic beyond a 90 nm technology node.