Presence of a voltage on this gate creates a conductive channel in the transistor, switching it on. The switching state of the field-effect transistor is controlled by the voltage on the control gate of the transistor. Each bit of the word is a 1 or 0, depending on the storage transistor being switched on or off, conducting or non-conducting.ДЄ cross-section of a floating-gate transistor To retrieve data from the EPROM, the address represented by the values at the address pins of the EPROM is decoded and used to connect one word (usually an 8-bit byte) of storage to the output buffer amplifiers. A control gate electrode is deposited and further oxide covers it. The floating-gate electrode has no connections to other parts of the integrated circuit and is completely insulated by the surrounding layers of oxide. An insulating layer of oxide is grown over the channel, then a conductive (silicon or aluminum) gate electrode is deposited, and a further thick layer of oxide is deposited over the gate electrode. Source and drain contacts are made to regions at the end of the channel. Each field-effect transistor consists of a channel in the semiconductor body of the device. Д®ach storage location of an EPROM consists of a single field-effect transistor. Frohman designed the Intel 1702, a 2048-bit EPROM, which was announced by Intel in 1971. Building on this concept, Dov Frohman of Intel invented EPROM in 1971, and was awarded U.S. In 1967, Dawon Kahng and Simon Min Sze at Bell Labs proposed that the floating gate of a MOSFET could be used for the cell of a reprogrammable ROM (read-only memory).

While he did not pursue it, this idea would later become the basis for EPROM technology. In 1963, he noted the movement of charge through oxide onto a gate.

Stored charge on these isolated gates changes their threshold voltage.ДЇollowing the invention of the MOSFET (metal-oxide-semiconductor field-effect transistor) by Mohamed Atalla and Dawon Kahng at Bell Labs, presented in 1960, Frank Wanlass studied MOSFET structures in the early 1960s. The small quartz window admits UV light for erasure.Дevelopment of the EPROM memory cell started with investigation of faulty integrated circuits where the gate connections of transistors had broken. An Intel 1702A EPROM, one of the earliest EPROM types (1971), 256 by 8 bit.

Chip life read write software