Antifuse Bypass Diode for Voltage Tolerance
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Solution Overview
Problem
Antifuse arrays in semiconductor devices face reliability issues due to the application of significant programming voltages, which can cause damage or impairment when negative voltages are applied to unselected antifuses during programming, leading to potential damage and reduced reliability.
Innovation Solution
Incorporating a first diode in parallel with the antifuse and a second diode in series, where the first diode acts as a bypass to reduce voltage across the antifuse during programming, and the second diode functions as a selector to manage leakage currents and prevent excessive voltage buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a significant programming voltage is applied to program an antifuse, then the antifuse can be programmed successfully, but negative voltage can be applied to unselected antifuses causing damage or reliability impairment
Solution Approach 1:
A bypass diode is introduced as an intermediary component connected in parallel with the antifuse. This diode acts as a mediator that provides a safe path for current flow when negative voltage is applied to unselected antifuses, preventing the harmful voltage from damaging the antifuse structure while allowing the programming voltage to function normally on selected antifuses
2Productivity
If antifuse arrays are arranged in rows and columns with row and column drivers, then large arrays can be accessed efficiently, but programming one antifuse applies corresponding negative voltage to other antifuses
Solution Approach 1:
The bypass diode serves as an intermediary that decouples the voltage interference problem from the array structure. It allows the row and column driver architecture to maintain its efficiency for accessing large arrays while simultaneously providing protection against the voltage interference that naturally occurs during programming operations
3Reliability
If programming voltage is applied to create a shorting path in the dielectric, then the antifuse is programmed, but the dielectric ruptures at the rupture point requiring high voltage
Solution Approach 1:
The bypass diode converts the harmful high voltage requirement into a beneficial protective mechanism. By providing an alternative current path through the diode, the system can handle the high programming voltages needed to rupture the dielectric without allowing these same high voltages to damage unselected antifuses, effectively turning the voltage requirement from a hazard into a controlled programming mechanism
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the ability of antifuse bitcells to tolerate programming voltages without damage, specifically limiting negative voltages applied to unselected antifuses and preventing voltage buildup, thereby improving the reliability of the antifuse array.
Implementation Method 1
a first diode coupled with the antifuse in a parallel combination
Implementation Method 2
a second diode coupled in series with the parallel combination
Data Source
AI summary
The embodiments described herein provide antifuse devices and methods that can be utilized in a wide variety of semiconductor devices. In one embodiment a semiconductor device is provided that includes an antifuse, a first diode coupled with the antifuse in a parallel combination, and a second diode coupled in series with the parallel combination. In such an embodiment the first diode effectively provides a bypass current path that can reduce the voltage across the antifuse when other antifuses are being programmed. As such, these embodiments can provide improved ability to tolerate programming voltages without damage or impairment of reliability.