OXIDE BREAKDOWN MOS FUSE AND UTILIZATION TO SAID MEMORY CARD

摘要

PURPOSE: To prevent the transition of a state by accumulation of electric charges by impressing an electric field larger than the breakdown threshold between the gate in silicon oxide and a doped region and obtaining the non- reversible breakdown of the oxide. CONSTITUTION: The terminal A of a fuse F1 is connected to a supply voltage VPP via a transistor T1 connected to a control terminal COMVPP and a terminal B is connected to the ground via T2 connected to a control terminal COMVSS. Next, the signal COMVPP of T2 is increased up to the voltage VPP and the signal COMVSS is made zero. The voltage of a node B is held afloat when T2 turns off and T1 turns on. Next, the voltage of the node B attains 0V when the voltage of a node A is VPP=20V. Then, the strong electric field of 20MV/cm exists in a tunnel window and the tunnel window is rapidly broken down. Consequently, the customization of memory card by the irreversible change of the structure of the circuit by the breakdown of the oxide is made possible.