Integrated Device Technology, Inc.

Sierra Semiconductor

Sik K Lui

David J Pilling

Raymond M Chu

Ying K Shum

A circuit improves the reliability of antifuses in certain types of systems by substantially eliminating the continuous undesirable applications of voltages across antifuse terminals. To accomplish this, an antifuse has applied across its two terminals a 'reading' or 'evaluation' voltage as required by the system operation for a single read or evaluation clock period (typically 5 ns to 30 ns in duration). The signal describing the state of the antifuse is then stored in a latch, register, or other suitable structure for subsequent sampling. In this manner, a low read current flows in the antifuse in response to the standard chip operating voltage for only a short period of time such as a single clock cycle. Thus, continuous voltages across the two terminals of the antifuse are avoided and an unprogrammed antifuse is not inadvertently programmed and a programmed antifuse is not inadvertently converted back to its high impedance state (i.e. 'unprogrammed'). In another embodiment, a multiplexer coupled to a terminal of the antifuse switches the terminal of the antifuse to a programming voltage node when the antifuse is selected for programming and to a reference voltage source when the antifuse is not selected for programming. The multiplexer prevents undesired voltages from being applied across the antifuse while other antifuses are being programmed. The two embodiments discussed may be used in conjunction with each other or separately.

Circuits for improving the reliability of antifuses in integrated

An antifuse redundancy circuit operates with transparency to external circuitry and users. In one embodiment, an antifuse redundancy circuit incorporates two antifuses rather than one. The circuit is arranged so that both antifuses may be simultaneously programmed and read. If a single antifuse is programmed without programming the other antifuse, the antifuse redundancy circuit will register a programmed antifuse. Additionally, if a single programmed antifuse is unintentionally deprogrammed after both antifuses in the redundancy circuit have been programmed, the antifuse redundancy circuit will continue to register a programmed antifuse. The result is both an increase in manufacturing yield and an increase in the reliability of integrated circuits utilizing antifuses.

Redundancy circuit for programmable integrated circuits

Circuits for improving the reliablity of antifuses in integrated circuits

A high resolution sense amplifier and method for sensing the state of antifuses in an integrated circuit is capable of correctly reading even a defectively programmed antifuse having a resistance of up to 20 K.OMEGA. as being programmed. The sense amplifier reads two antifuses at each programmable location, and correctly reads that location as being programmed if either or both of the antifuses at that location have been blown.

High resolution circuit and method for sensing antifuses

A semiconductor structure having a high precision analog polysilicon capacitor with a self-aligned extrinsic base region of a bipolar transistor is disclosed. The structure is formed by simultaneously forming the dielectric layer of the capacitor with the formation of the base region of the bipolar transistor. A final oxidation step in the formation of the capacitor causes the base region to diffuse to form a self-aligned extrinsic base diffusion region.

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Sunnyvale, CA, United States of America

Sik K Lui