FinFET Bias Temperature Instability Prediction via Transient Simulation
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Solution Overview
Problem
Conventional methods for calculating bias temperature instability (BTI) in FinFET and MOSFET devices are inadequate, as they rely on simple mathematical models that fail to account for the complex degradation recovery processes, which are device-state dependent, limiting their applicability to advanced transistor technologies.
Innovation Solution
A method for calculating BTI using device degradation history, where transient analysis simulations determine degradation and recovery values at each time step, allowing for the combination of stress degradation and recovery to predict long-term device performance, independent of specific mathematical models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simple mathematical models (power law or logarithmic equations) are used to calculate BTI degradation, then the calculation process is simple and fast, but the prediction accuracy is insufficient for FinFET devices
Solution Approach 1:
The patent divides the continuous degradation process into discrete time steps, calculating degradation and recovery separately at each step. This segmentation allows the model to capture the step-dependent recovery behavior while maintaining computational efficiency through incremental updates rather than solving complex continuous equations.
Solution Approach 2:
The patent implements feedback by using the current degradation state as input for calculating recovery at each time step. The recovery amount depends on the accumulated degradation history, creating a feedback loop that accurately models the state-dependent recovery process observed in FinFET devices while building upon the simple incremental structure.
2Measurement precision
If complex mathematical models accounting for degradation state dependence are used, then the prediction accuracy improves for FinFET devices, but the calculation complexity increases
Solution Approach 1:
The patent segments the complex degradation-recovery process into manageable discrete time steps, where at each step only simple calculations are performed based on current state. This avoids the need for complex continuous mathematical models while capturing the essential state-dependent behavior through incremental updates.
Solution Approach 2:
The patent makes the recovery model dynamic by allowing recovery parameters to change based on the current degradation state at each time step. This dynamic approach captures the state-dependent recovery behavior without requiring a static complex mathematical model, as the simplicity is maintained at each step while the overall behavior becomes sophisticated.
3Productivity
If conventional BTI calculation methods are used, then the calculation is computationally efficient, but the method cannot accurately model FinFET degradation recovery
Solution Approach 1:
The patent creates a universal calculation framework that works for both conventional MOSFET and advanced FinFET devices. The discrete time-step approach with state-dependent recovery is general enough to handle different device types while maintaining computational efficiency, making the method versatile across technology nodes without requiring device-specific complex models.
Solution Approach 2:
The patent introduces dynamic state-dependence into the recovery calculation, allowing the model to adapt to FinFET behavior where recovery depends on current degradation state. This dynamic element provides the necessary adaptability for FinFET while maintaining the computational efficiency of incremental calculations rather than solving complex device-specific equations.
Data Source
AI summary
A method, a system and a non-transitory machine-readable storage medium are provided. In one or more aspects, a computer-implemented method for bias temperature instability (BTI) calculation of a device includes simulating the device, using an electronic design automation tool. The simulation includes determining a first degradation value after applying a first sequence of stress values to the device for a first plurality of time steps. The simulation further includes determining a first degradation recovery value after the first plurality of time steps. The simulation further includes determining a first recovered degradation value after the first plurality of time steps by combining the first degradation value and the first degradation recovery value. The first degradation value, the first degradation recovery value, and the first recovered degradation value are associated with one or more model parameters of the device. The simulation is a transient analysis simulation, and the device is a FINFET or MOSFET device.