Multilevel Anti-Fuse Cells By Progressive Rupturing Of The High-Kappa Gate Dielectric In Finfet Technologies

A new operation scheme is proposed for achieving multilevel storage in FinFET one-time programmable (OTP) cells by a high-kappa metal gate CMOS process. The OTP cells are programmed by breaking down the gate dielectric layer, during which the corner effect in the FinFET structure shortens the program time and lowers the program voltages. The after-breakdown resistance in the storage node is found to be well-controlled by the compliance current level set by the select transistor. By using WL voltage control, the multilevel OTP cell with superior data retention and disturb immunity is successfully used in advanced logic nonvolatile memory applications.