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, {HEAD ~ laser beams} irradiating selected silicon resistances to thermally activate those resistances and store {TAIL ~ the required data} 
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 , { HEAD ~ laser beams } irradiating selected silicon resistances to thermally activate those resistances and store { TAIL ~ the required data }
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