Random access electrically programmable e-fuse ROM
First Claim
1. A programmable device comprisinga plurality of cells, each cell having a long dimension and a short dimension, each said cell comprisingan e-fuse, anda transistor in series with said e-fuse and having a control electrode connected to a word line and a conduction path connected to a sense line, said transistor and said e-fuse having their long dimensions substantially aligned with a long dimension of said cell and said word line located substantially parallel to said long dimension of said cell,a bit line crossing a short dimension of at least two of said plurality of cells, anda sense amplifier connected to said bit line.
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Accused Products
Abstract
A one-time-programmable-read-only-memory (OTPROM) is implemented in a two-dimensional array of aggressively scaled suicide migratable e-fuses. Word line selection is performed by decoding logic operating at VDD while the bit line drive is switched between VDD and a higher voltage, Vp, for programming. The OTPROM is thus compatible with and can be integrated with other technologies without a cost adder and supports optimization of the high current path for minimal voltage drop during fuse programming. A differential sense amplifier with a programmable reference is used for improved sense margins and can support an entire bit line rather than sense amplifiers being provided for individual fuses.
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Citations
35 Claims
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1. A programmable device comprising
a plurality of cells, each cell having a long dimension and a short dimension, each said cell comprising an e-fuse, and a transistor in series with said e-fuse and having a control electrode connected to a word line and a conduction path connected to a sense line, said transistor and said e-fuse having their long dimensions substantially aligned with a long dimension of said cell and said word line located substantially parallel to said long dimension of said cell, a bit line crossing a short dimension of at least two of said plurality of cells, and a sense amplifier connected to said bit line.
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28. An e-fuse for an integrated circuit comprising
a first terminal having a length corresponding to a width of a conductor connected thereto, and a second terminal having a geometry for concentrating current flux density, said e-fuse having an unprogrammed resistance of less than 180Ω
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31. A programmable device comprising
a semiconductor chip, a two-dimensional array of memory cells, each memory cell comprising an e-fuse connected to a bit line and a transistor connected in series with said e-fuse and having a control electrode of said transistor connected to a word line, a decoder for selectively applying a first voltage to said word line, a selector for selectively applying one of said first voltage and a second voltage to said bit line, said second voltage being greater than said first voltage, and a source of said second voltage, wherein said two-dimensional array of memory cells, said decoder, said selector and said source of said second voltage are formed on said semiconductor chip.
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33. A method for programming an e-fuse having a transistor in series therewith, said method comprising steps of
applying a programming voltage to said e-fuse, controlling conduction of said transistor with a voltage less than said programming voltage whereby said transistor initially conducts in a saturation mode and, in a linear mode, applies a voltage across said e-fuse following programming of said e-fuse.
Specification