Abstract: A late programming mask ROM integrated circuit and a process for producing the same. The mask ROM integrated circuit has a silicon substrate, and a plurality of memory cells formed on the silicon substrate. Each memory cell consists of a transistor element and a diode element electrically connected in series. Each transistor element has a drain layer, a channel layer, a source layer all stacked on the silicon substrate in a substantially vertical direction to form an upright drain/channel/source structure region, and a gate electrode region formed on the silicon substrate. The gate electrode regions and the upright drain/channel/source structure regions of the transistor elements are alternately arranged in an adjacent fashion along a substantially horizontal direction. Each diode element is formed by one upright drain/channel/source structure and a diode layer formed on or under the upright drain/channel/source structure.

Abstract: A late programming mask ROM integrated circuit and a process for producing the same. The mask ROM integrated circuit has a silicon substrate, and a plurality of memory cells formed on the silicon substrate. Each memory cell consists of a transistor element and a diode element electrically connected in series. Each transistor element has a drain layer, a channel layer, a source layer all stacked on the silicon substrate in a substantially vertical direction to form an upright drain/channel/source structure region, and a gate electrode region formed on the silicon substrate. The gate electrode regions and the upright drain/channel/source structure regions of the transistor elements are alternately arranged in an adjacent fashion along a substantially horizontal direction. Each diode element is formed by one upright drain/channel/source structure and a diode layer formed on or under the upright drain/channel/source structure.