Non-volatile memories (NVMs) are essential for a variety of embedded applications such as encryption keys, code storage, and analog trimming. One of the lowest-cost non-volatile memories is the one-time programmable (OTP) memory. Most of the existing OTP memories are fabricated with special processes where extra masks are added to a standard CMOS process. It is, however, still necessary to develop an OTP memory in a pure CMOS process to further reduce the cost for many applications such as radio frequency identification (RFID) tags....[ Read more ]

Non-volatile memories (NVMs) are essential for a variety of embedded applications such as encryption keys, code storage, and analog trimming. One of the lowest-cost non-volatile memories is the one-time programmable (OTP) memory. Most of the existing OTP memories are fabricated with special processes where extra masks are added to a standard CMOS process. It is, however, still necessary to develop an OTP memory in a pure CMOS process to further reduce the cost for many applications such as radio frequency identification (RFID) tags.

Different from conventional OTP memory designs, the targeted embedded applications in this work require ultra-low power consumption in both the read and the write operations. Because of that, power reduction strategies are provided during memory cell and circuit designs. Owing to the need for high voltages during write operations, gate-oxide reliability is also a major concern. To solve all the high voltage problems in the memory circuit, the Cascode technique is used extensively to maintain programming reliability.

Various anti-fuse memory elements manufactured with a standard 0.18μm CMOS process from a major foundry are compared and the gate-oxide anti-fuse (GOAF) is chosen as the most suitable one when programming current is seriously constrained. Different combinations of GOAF memory cells have been fabricated, measured, and studied. A complete GOAF OTP memory circuit has been designed and fabricated with the above process. The functions of each part are described and measurement results are shown and analyzed in this thesis.