One-time programmable memory, or OTP, is a form of digital memory in which the setting of each bit of information is locked by a fuse or antifuse, meaning that data cannot be added or erased. This type of memory is used in many different electronic consumer products, such as video games, cell phones, TVs and vehicle systems.
OTP memory was invented by Wen Tsing Chow of the American Bosch Arma Corporation in 1956 at the request of the US Air Force.
The Air Force was looking for a flexible and secure way for the Atlas E/F ICBM's airborne digital computer to store targeting constants. The patent for OTP and associated technology was kept classified for several years while the Atlas E/F was the main operational missile of the United States ICBM force. Consequently, all of the earliest machines utilizing PROM technology were also developed under Mr. Chow's direction by Arma engineers. They are now located in Arma's Garden City lab and in the US Air Force Strategic Air Command headquarters.
Machines using some form of OTP memory have been available on the commercial market since at least 1969, and in 1979Texas Instruments developed a MOS gate-oxide breakdown antifuse. Two years later a dual-gate-oxide two-transistor MOS antifuse was introduced on the market, however due to a series of manufacturing problems in early production, oxide breakdown technologies were prevented from being produced in large volume.
In November of 2005 a new breakthrough antifuse bit cell called a Split Channel device was introduced by Sidense. This Split Channel bit cell combines the thick and thin oxide devices into one transistor with a common polysilicon gate.
A typical OTP memory is created with a bits reading of 1. A 0 bit reading is created by burning a fuse bit during programming. The memory can be programmed just once after manufacturing by the irreversible process of blowing the fuses. Blowing a fuse opens a connection while programming an antifuse closes a connection.
The programming process involves applying a high-voltage pulse across the gate and substrate of the thin oxide transistor that is not normally encountered during operation. The pulse results in a break-down of the oxide between the gate and substrate. A tunneling current flowing through the oxide is created by the positive voltage on the transistor's gate forming an inversion channel in the substrate below the gate. The current ultimately melts the oxide and forms a conductive channel from gate to substrate.
All varieties of OTP memory have their pros and cons, but the advent of this type of digital memory has revolutionized a spectrum of markets from missile technology to flat screen TV's. Advances in the field of digital memory are certain to be enthusiastically greeted by engineers and scientists around the globe.
Author Resource:
Novocell Semiconductor Inc. (http://www.novocellsemi.com/) has become the foundation of a growing semiconductor industry and otp memory in the Pittsburgh region. Art Gib is a freelance writer.
![[Valid RSS feed]](http://www.look4articles.com/images/icon_Rss.png "XML Feed For RSS"){kind=icon}
Category Rss Feed
Print This Article
Add To Favorites
![[Valid RSS feed]](http://www.look4articles.com/images/rss.jpg "XML Feed For RSS")