High density ROM

摘要

A ROM is formed by depositing a first layer composed of a material selected from polysilicon and polycide on the substrate, patterning the first layer by masking and etching, depositing a dielectric layer over the first layer and patterning the dielectric layer and the first layer into the pattern of first conductor lines, forming a contact window through the dielectric layer down to the substrate, depositing a second layer composed of a material selected from polysilicon and polycide on the device and forming second conductor lines directed orthogonally to the first conductor lines formed from the first layer, and ion implanting into the substrate through the second layer to form a contact region electrically connected to the second conductor lines of the second layer.