A New High-Density Twin-Gate Isolation One-Time Programmable Memory Cell in Pure 28-nm CMOS Logic Process

A new and compact high-k dielectric breakdown one-time programmable (OTP) cell in pure 28-nm high-k metal gate (HKMG) process is proposed. By adopting a self-aligned twin-gate isolation (TGI) made by merged gate spacer, the new OTP cell can operate independently with a very small cell area. Fabricated by a pure 28-nm HKMG CMOS logic process, this OTP cell successfully achieves an ultrasmall cell size of 0.0441 μm2 on 28-nm HKMG CMOS logic platform. Using high-k dielectric breakdown as its program mechanism, the antifuse TGI OTP memory has more than three orders of ON/OFF read window with a low program voltage of 4 V in 20 μs. Furthermore, a highly density 64-kbit TGI OTP array has been fabricated and successfully demonstrates the new superior isolation and reliability performances.