BTI Oscillator Clock Gating for Transistor Reliability
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Solution Overview
Problem
Bias temperature instability (BTI) causes degradation in transistors within semiconductor memory devices, particularly due to rapid oscillation of clock signals, leading to conflicts between BTI toggle signals and access operations, and existing solutions fail to effectively control BTI toggle signals in both clocked and unclocked modes.
Innovation Solution
Incorporating a BTI oscillator to generate a periodic BTI signal synchronized with the clock signal, which is then used by a clock gating circuit to control the clock path, and during unclocked modes, the BTI signal is provided to the clock input buffer, allowing seamless transition and mitigating BTI degradation without interfering with access operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BTI toggle signal is applied to mitigate transistor degradation, then transistor reliability is improved, but conflicts arise with access operations due to signal interference
Solution Approach 1:
The patent applies periodic action by implementing BTI mitigation toggle sequences that periodically switch gate voltages at specific intervals (e.g., every 256 microoperations or at designated clock cycles). This periodic toggling mitigates transistor degradation while the timing is carefully coordinated to avoid conflicting with access operations, thus resolving the signal interference problem.
Solution Approach 2:
The patent employs preliminary action by proactively scheduling BTI toggle sequences in advance at predetermined intervals during idle periods or between access operations. The control circuit pre-plans when to apply gate voltage toggles based on predicted idle windows, ensuring BTI mitigation occurs before degradation becomes critical while maintaining compatibility with upcoming access operations.
2Reliability
If gate voltage is periodically toggled to mitigate BTI, then transistor degradation is reduced, but control complexity increases to prevent conflicts with access operations
Solution Approach 1:
The patent merges the BTI mitigation control function with the existing microoperation control circuitry. The control circuit integrates BTI toggle generation, timing coordination, and access operation management into a unified control unit that shares resources with the microoperation sequencing logic, thereby reducing overall control complexity while maintaining effective BTI mitigation.
Solution Approach 2:
The control circuit automatically manages BTI mitigation by autonomously generating toggle sequences and coordinating them with access operations without requiring external intervention. The system self-regulates the timing and frequency of gate voltage toggles based on its own operational state, simplifying the control architecture while ensuring reliable BTI protection.
3Reliability
If BTI mitigation operations are performed frequently, then transistor reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic BTI mitigation where gate voltage toggles are applied at optimized intervals (e.g., every 256 microoperations or during idle periods) rather than continuously. This periodic approach maintains transistor reliability by regularly counteracting degradation while significantly reducing power consumption compared to continuous toggling, as the mitigation operations are confined to specific time windows.
Solution Approach 2:
The patent applies partial action by performing BTI mitigation only during idle periods or at specific intervals rather than during all operational cycles. The control circuit selectively enables gate voltage toggles only when access operations are not occurring, providing sufficient BTI protection during critical periods while minimizing power consumption during active data access when toggling would be unnecessary or harmful.
Data Source
AI summary
Apparatuses, systems, and methods for bias temperature instability (BTI) mitigation. A BTI oscillator provides a periodic BTI signal. A BTI logic circuit generates a BTI pulse signal based on the periodic BTI signal and synchronized to a clock signal. A clock gating circuit passes the clock signal to a clock path when the periodic BTI signal is active. When the memory is in an unclocked mode, where an external clock is not received, the periodic BTI signal is provided to a clock input buffer and passed as the clock signal.