Mask programmable read-only memory stacked above a semiconductor substrate

Abstract From the Canadian patent

In the disclosed read-only memory, address decode means for addressing information in the memory lie in a semiconductor substrate; an insulating layer covers the address decode means; an array of spaced-apart metal lines and semiconductor lines lies on the insulating layer over the address decode means; outputs from the address decode means respectively couple through the insulating layer to the metal lines and to the semiconductor lines; and a plurality of mask selectable electrical contacts between the metal lines and semiconductor lines forms a matrix of mask selectable diodes over the insulating layer representative of the information in the memory.