One-time programming in reprogrammable memory

Abstract

A portion of a reprogrammable storage device is used to implement permanent data storage. The storage device includes a plurality of electrically erasable memory elements and a controller. The plurality of electrically erasable memory elements are configured to store data. Each memory element is programmable a number of write cycles before reaching a write failure state. The controller is coupled to the plurality of memory elements. The controller includes a receiver and a write engine. The receiver receives an instruction to drive a selected memory element to the write failure state. The write engine repeatedly writes a data value, in a plurality of write operations, to the selected memory element until the write failure state of the selected memory element is established.

Description

Background technique [0001] Electronic storage devices may generally be classified as one-time programmable (OTP) storage devices or reprogrammable storage devices. There is another type of specialized memory known as Multiple Time Programmable (MTP) memory, which involves changes to the wafer production process. [0002] OTP memory devices have memory elements accompanied by fuses and antifuses. Once a data value is programmed into the OTP storage element, a fuse is blown to create a permanently open circuit, or an anti-fuse is programmed to create a permanently closed circuit. This prevents the OTP storage elements from being reprogrammed to store different data values. OTP storage elements hold written data values ​​indefinitely, or as long as the stored state can be physically maintained by the storage element (data retention can be limited by electron drift through insulators such as floating gate transistors middle). [0003] Reprogrammable storage devices allow indi...

AI Technical Summary

Problems solved by technology

Replication of memory devices can be very costly in terms of design time and die size

Furthermore, OTP memory devices consume relatively large silicon area compared to some types of reprogrammable memory devices

Furthermore, OTP memory devices are susceptible to hardware investigation and unauthorized bit recovery (e.g., using an electron microscope), while at least some types of reprogrammable memory devices cannot be easily investigated or read

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