CIRCUIT FOR ENCODING IDENTIFICATION INFORMATION ON CIRCUIT DIE

摘要

PURPOSE: To obtain a programmable circuit for encoding data on a circuit die using an MOSFET or IGFET capacitor structure as a binary data memory bit. CONSTITUTION: The gate 14 of MOSFET or IGFET 12 functions as the first voltage of a capacitor and both of the source 16 and drain 18 thereof are connected to second voltage to function as the second voltage plate of the capacitor. Usually, an open circuit is present between the gate 14 and the source 16 but, when programming high voltage is applied to the gate, the structure of the capacitor is destructed physically to form a conductive path between the gate and the source or drain. The presence and absence of the conductive path enable an MOSFET or IGFET capacitor structure to function as a binary bit. A read circuit detects the presence or absence of the conductive path and a multiplexer can be employed in order to successively connect the read circuit to a plurality of the same structures.