History of electrochemistry
In 1789, Franz Aepinus developed a device with the properties of a "condenser" (now known as a capacitor.) The Aepinus condenser was the first capacitor developed after the Leyden jar, and was used to demonstrate conduction and induction. The device was constructed so that the space between two plates could be adjusted, and the glass dielectric separating the two plates could be removed or replaced with other materials.
EPROM
Development of the EPROM memory cell started with investigation of faulty integrated circuits where the gate connections of transistors had broken. Stored charge on these isolated gates changed their properties. The EPROM was invented by Dov Frohman of Intel in 1971, who was awarded US patent 3660819 in 1972.
Each storage location of an EPROM consists of a single field-effect transistor. Each field-effect transistor consists of a channel in the semiconductor body of the device. Source and drain contacts are made to regions at the end of the channel. 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. The floating-gate electrode has no connections to other parts of the integrated circuit and is completely insulated by the surrounding layers of oxide. A control gate electrode is deposited and further oxide covers it.