P-ROM Cell having a low current fusible programming link
AssigneeMotorola, Inc.
InventorWalter Lee Davis
Life of this patent
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Abstract
A programmable cell for a P-ROM (programmable read only memory) matrix includes a bipolar transistor having a fusible link in one of the transistor leads on the substrate. The fusible link is a "necked-down" portion of one of the leads, positioned adjacent the base-collector junction where it is heated by the junction current, causing the links to open at a low fusing current.
Claims6
A permanently alterable semiconductor cell comprising at least a transistor and a fusible elements, the fusible element being coupled in series with an element of said transistor for being fused by a predetermined current through said transistor, said predetermined current being substantially greater than the normal operating current of said transistor, the fusible element being positioned for receiving thermal energy from a junction region of said transistor whereby the predetermined current required for fusing the element is substantially reduced due to said thermal energy.
An integrated circuit programmable read only memory comprising:
- a plurality of cells interconnected to form an array of rows and columns, each cell containing at least a transistor and a fusible element, said fusible element coupled in series with an element of said transistor for being fused by a predetermined current through said transistor, said predetermined current being substantially greater than the normal operating current of said transistor, the fusible element positioned for receiving thermal energy from a junction region of said transistor, whereby the predetermined current required for fusing the element is substantially reduced due to said thermal energy.
Dependencies are inferred from the claim text.