Vertical MOS Transistor Monitoring With On-Substrate Reference FET
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Solution Overview
Problem
The electrical characteristics of MOS gate semiconductor devices vary significantly due to manufacturing differences, leading to instability in circuit operation over time, even when elements with similar characteristics are selected for parallel use in circuits like three-phase bridge circuits.
Innovation Solution
A semiconductor device configuration that includes both vertical and horizontal semiconductor transistors on the same semiconductor base, where the gate electrodes, source electrodes, and drain electrodes are electrically connected, allowing the electrical characteristics of the vertical transistor to be predicted by measuring those of the horizontal transistor, which has a higher threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If elements with similar electrical characteristics are selected during assembly, then initial circuit performance is improved, but electrical characteristic stability over time deteriorates
Solution Approach 1:
The patent applies preliminary action by forming a monitor transistor on the same semiconductor substrate as the main transistor before circuit assembly. This monitor transistor serves as a built-in reference that undergoes the same manufacturing variations and aging processes, allowing prediction of future electrical characteristic changes before the circuit is deployed. The threshold voltage of the main transistor is determined based on the monitor transistor's characteristics, establishing a baseline that accounts for inherent variations.
Solution Approach 2:
The patent implements feedback by using the monitor transistor's electrical characteristics to continuously track and predict changes in the main transistor's performance over time. By monitoring the monitor transistor's threshold voltage variations under the same operating conditions, the system can detect drift in the main transistor's characteristics and compensate for it, maintaining circuit stability throughout the operational lifecycle.
2Power
If multiple elements are used in parallel to improve circuit performance, then power handling capability is improved, but variation in electrical characteristics worsens
Solution Approach 1:
The patent applies local quality by creating a localized reference system (monitor transistor) on the same substrate as each main transistor or transistor group. This localized approach ensures that the monitor captures the specific manufacturing variations and environmental conditions affecting that particular main transistor, enabling precise compensation for parallel element variations without requiring global calibration.
Data Source
AI summary
An object is to provide a technology capable of predicting fluctuation in electrical characteristics of vertical semiconductor transistors when operated in the market. The semiconductor device includes a vertical semiconductor transistor and a horizontal semiconductor transistor provided on the same semiconductor base. A gate electrode of the vertical semiconductor transistor and a gate electrode of the horizontal semiconductor transistor are electrically connected. A source electrode of the vertical semiconductor transistor and a source electrode of the horizontal semiconductor transistor are electrically connected.