Antifuse programming by transistor snap-back
First Claim
1. A method to program a one time programmable element in an integrated circuit, said method comprising the steps of:
- a) applying a first biasing voltage to a first terminal of said transistor;
b) applying a first voltage pulse to a second terminal of said transistor, said applications of first biasing voltage and said first voltage pulse cause said programmable element to rupture;
c) applying a second biasing voltage to said transistor'"'"'s first terminal, said second biasing voltage is at a potential less than that of said first biasing voltage; and
d) applying a second voltage pulse to said transistor'"'"'s second terminal thereby causing transistor snap-back which allows a surge of current to flow through said ruptured element.
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Abstract
The present invention comprises a method to program antifuse elements in integrated circuits, such as programmable read-only memory (PROM) or option selections/redundancy repair on dynamic random access memories (DRAMs) by utilizing the phenomenon of transistor snap-back. Multiple programming pulses are applied to an NMOS transistor which provides access to the desired antifuse element. The first pulses applied ruptures the antifuse element causing it so become a resistive short. The second programming pulses cause the access NMOS transistor to go into snap-back thus allowing a surge of current to flow through the resistively shorted antifuse thereby lowering the resistance of the shorted antifuse element substantially allowing for less power consumption and higher reliability of the permanently programmed element.
57 Citations
22 Claims
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1. A method to program a one time programmable element in an integrated circuit, said method comprising the steps of:
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a) applying a first biasing voltage to a first terminal of said transistor; b) applying a first voltage pulse to a second terminal of said transistor, said applications of first biasing voltage and said first voltage pulse cause said programmable element to rupture; c) applying a second biasing voltage to said transistor'"'"'s first terminal, said second biasing voltage is at a potential less than that of said first biasing voltage; and d) applying a second voltage pulse to said transistor'"'"'s second terminal thereby causing transistor snap-back which allows a surge of current to flow through said ruptured element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method to program a one time programmable antifuse element in an integrated circuit, said method comprising the steps of:
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a) applying a first biasing voltage to a first transistor'"'"'s terminal; b) applying a first voltage pulse to a second terminal of said transistor, said applications of first biasing voltage and said first voltage pulse cause said antifuse element to rupture thereby becoming a resistive short; c) applying a second biasing voltage to said transistor'"'"'s first terminal, said second biasing voltage being at a potential less than that of said first biasing voltage; and d) applying a second voltage pulse to said second transistor terminal thereby causing transistor snap-back which allows a surge of current to flow through said resistive short and thereby reducing the resistance by approximately one order of magnitude. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method to program an antifuse element in a programmable read only memory, said method comprising the steps of:
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a) applying a first gate voltage via a word line to the gate of an NMOS transistor; b) applying a first voltage pulse via a digit line to the drain of said NMOS transistor, said applications of first gate voltage and said first voltage pulse cause said antifuse element to rupture thereby becoming a resistive short; c) applying a second gate voltage via said word line to said gate of said NMOS transistor, said second gate voltage being at a potential less than that of said first gate voltage; and d) applying a second voltage pulse to said transistor'"'"'s drain thereby causing transistor snap-back which allows a surge of drain current to flow through said resistive short and thereby reducing the resistance by approximately one order of magnitude.
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Specification