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US 4,565,712 AGranted
Method of making a semiconductor read only memory
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorsHideo Noguchi, Tugunari Iwamoto, Sakae Takei
Life of this patent
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Abstract
A semiconductor read only memory having a plurality of MOS transistors and polycrystalline or amorphous silicon resistances connected to the source or drain regions of the MOS transistors, laser beams irradiating selected silicon resistances to thermally activate those resistances and store the required data.
Claims3
A method of manufacturing a semiconductor read only memory comprising the steps of:
- forming a plurality of MOS transistors on the surface of a semiconductor substrate,
- connecting a plurality of silicon resistances to source and drain regions of said MOS transistors respectively,
- forming an insulator film on the surface of said substrate to provide an unactivated ROM, and
- irradiating with a laser beam selected silicon resistances through said insulator film to activate said ROM.
1 more element
Dependencies are inferred from the claim text.