Semiconductor Gate Trench Uniformity for Capacitance Stability
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Solution Overview
Problem
Semiconductor devices with constant intervals between all trenches, including gate and dummy trenches, exhibit peculiar capacitance characteristics, leading to potential oscillation or malfunction due to non-uniformity in dummy trench intervals.
Innovation Solution
The semiconductor device design features gate trenches and dummy trenches with neighboring intervals adjusted such that the interval between a gate trench and a dummy trench is shorter than the interval between neighboring dummy trenches, ensuring uniformity and improving capacitance characteristics by achieving a parallel-plate capacitor approximation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all trenches including gate trenches and dummy trenches are provided at constant intervals, then manufacturing is simplified, but the semiconductor device exhibits peculiar capacitance characteristics that may cause oscillation or malfunction
Solution Approach 1:
The patent segments the trench structure into two distinct types: gate trenches containing functional gate electrodes and dummy trenches containing dummy gate electrodes. By differentiating the intervals between these two types of trenches (with the interval between gate trench and dummy gate trench being shorter than the interval between neighboring dummy gate trenches), the patent achieves uniform dummy trench spacing while maintaining reliable capacitance characteristics, thus resolving the contradiction between manufacturing simplicity and device reliability.
2Reliability
If dummy trenches are formed with non-uniform intervals relative to gate trenches, then capacitance characteristics are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by establishing different interval specifications for different regions of the trench structure. Specifically, the interval between a gate trench and its neighboring dummy gate trench is set to be shorter than the interval between neighboring dummy gate trenches. This localized differentiation in spacing allows the patent to achieve uniform dummy trench intervals (simplifying manufacturing) while simultaneously improving capacitance characteristics through controlled non-uniformity in the overall trench pattern.
Data Source
AI summary
Plural gate trenches are formed on an upper surface side of a semiconductor substrate of a first conductivity type. Gate electrodes are embedded in the plural gate trenches. Plural dummy gate trenches are formed at equivalent intervals between the neighboring gate trenches on the upper surface side of the semiconductor substrate. Dummy gate electrodes are embedded in the plural dummy gate trenches and connected with an emitter electrode. An interval between the gate trench and the dummy gate trench that neighbor each other is shorter than an interval between the neighboring dummy gate trenches.