US 7,923,813 B2Granted

Anti-fuse memory device

AssigneeNXP B.V.

InventorsPaul Van Der Sluis, Andrei Mijiritskii, Pierre H. Woerlee, Victor M. G Van Acht, Nicolaas Lambert

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Abstract

A One Time Programmable (OTP) memory cell (10) comprising a first, metallic layer (12) coated with a second, conductive stable transition compound (14) with an insulating layer (16) there-between. The first and second layers (12, 14) are selected according to the difference in Gibbs Free Energy between them, which dictates the chemical energy that will be generated as a result of an exothermic chemical reaction between the two materials. The materials of the first and second layers (12, 14) are highly thermally stable in themselves but, when a voltage is applied to the cell (10), a localized breakdown of the insulative layer (16) results which creates a hotspot (18) that sets off an exothermic chemical reaction between the first and second layers (12, 14). The exothermic reaction generates sufficient heat (20) to create a short circuit across the cell and therefore reduce the resistance thereof.

Claims10

Dependent claims

A method of manufacturing a non-volatile memory cell having an anti-fuse connected to at least two terminals, the anti-fuse being programmable by applying a voltage across said terminals so as to change the resistance of the anti-fuse from a first, relatively high resistance representative of a first logical bit value to a second, relatively low resistance representative of a second logical bit value, the method comprising

the step of forming a stack comprising a plurality of layers of materials including a first layer of a conductive material and a second layer of a conductive material with a layer of an insulative material therebetween;
said second conductive material comprising a stable compound, said layer of the insulative material being such that the application of said voltage to said anti-fuse causes a localized breakdown of said insulative layer,
the method further comprising the step of selecting said first and second layers of the conductive materials such that the heat created by said localized breakdown of said insulative material initiates an exothermic chemical reaction therebetween so as to generate a sufficient energy in said anti-fuse to change the state of at least a portion of one of said layers of said stack and create a stable short circuit between said terminals and reduce the resistance of said anti-fuse from said first, relatively high resistance to said second, relatively low resistance,
wherein the anti-fuse further includes a layer of an amorphous phase change material provided between the terminals and positioned adjacent to the first and second layers of the conductive materials and the layer of the insulative material such that the layer of the amorphous phase change material directly contacts both the first and second layers of the conductive materials, wherein the amorphous phase change material is selected such that the energy generated in the anti-fuse as a result of the exothermic chemical reaction causes it to change to a conductive crystalline phase change material thereby creating a short circuit between the terminals.

1 more element

A non-volatile memory cell having an anti-fuse connected to at least two terminals, the anti-fuse being programmable by applying a voltage between said terminals, so as to change the resistance of the anti-fuse from a first, relatively high resistance representative of a first logical bit value to a second, relatively low resistance representative of a second logical bit value, said anti-fuse comprising

a stack comprising a plurality of layers of materials including a first layer of a conductive material coated with a second layer of a conductive material with an insulative layer therebetween, said second conductive material comprising a stable compound, wherein the application of said voltage to said anti-fuse causes a localized breakdown of said insulative layer, said first and second layers of the conductive materials being selected such that the heat created by said localized breakdown of said insulative layer initiates an exothermic chemical reaction therebetween so as to generate a sufficient energy in said anti-fuse to change the state or chemical composition of at least a portion of one of said layers of said anti-fuse and create a stable short circuit between said terminals and reduce the resistance of said anti-fuse from said first, relatively high, resistance to said second, relatively low resistance,
wherein the anti-fuse further includes a layer of an amorphous phase change material provided between the terminals and positioned adjacent to the first and second layers of the conductive material and the layer of the insulative material such that the layer of the amorphous phase change material directly contacts both the first and second layers of the conductive materials, which the amorphous phase change material is selected such that the energy generated in the anti-fuse as a result of the exothermic chemical reaction causes it to change to a conductive crystalline phase change material thereby creating a short circuit between the terminals.

Dependencies are inferred from the claim text.

Facts

Application: 11/914,662Filed 4 May 2006
Priority: EP 0510437824 May 2005
Published: US 2009/0072212 A119 Mar 2009
Granted: 12 Apr 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G11C 17/16
In which contents are determined by selectively establishing, breaking or modifying connecting links by permanently altering the state of…
H10B 20/00
Read-only memory [rom] devices
H10B 20/25
Programmable ROM [PROM] devices comprising field-effect components: one-time programmable ROM [OTPROM] devices, e.g. using electrically-fusible links
H10W 20/491
Adaptable interconnections, e.g. fuses or antifuses: antifuses, i.e. interconnections changeable from non-conductive to conductive