IMPEDANCE PROGRAMMABLE SEMICONDUCTOR STRUCTURES

摘要

803 A solid state semiconductor device is disclosed which is programmable so as to alter the impedance between its two terminals. In many embodiments, the device is programmable to have any one of four conditions: a first in which the electrical impedance is relatively high in both directions; a second in which the impedance is relatively high in one direction and relatively low in the opposite direction; a third in which the impedance is relatively high in the opposite direction and relativley low in the first direction; and a fourth in which the impedance is relatively low in both directions. Such a programmable device can be made with semiconductor layers which form two series coupled back-to-back diodes, each of which can be selectively programmed to lose its rectifying features. Structures are disclosed which include a plurality of such programmable devices in one or more separately programmable planes, each with its own addressing means. Programmable logic arrays can be formed out of such multilayered cell structures, including programmable logic arrays, in which the AND and OR planes are vertically disposed one on top of the other. 606b