Electronic matrix arrays and method for making, parallel preprogramming or field programming the same

A method of making a parallel programmed electronic matrix array includes forming at least one layer of a phase changeable material on a conductive substrate, the material preferably formed of amorphous material and having substantially nonconductive and comparatively high conductive states, and irradiating selected areas of the layer to convert them to the other state. Thereafter, in a preprogrammed embodiment, first and second sets of electrically conductive address lines are formed on respective opposite sides of the layer such that they cross each other at an angle to form a plurality of crossover points. In a field programmable array, the selected areas are irradiated through one set of lines.In accordance with another embodiment, the selected areas are irradiated through a mask. One set of lines is preferably formed by removing portions of the conductive substrate. The other can be formed by detecting the locations of the layer portions of one of the states and aligning the lines on the layer according to such detection.A diode structure can be formed with or in place of the phase changeable material.