Semiconductor Device Stripe Trenches Prevent Cavity Formation
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Solution Overview
Problem
The formation of cavity areas in the drift region of semiconductor devices due to non-uniform deep trench embedding leads to reduced breakdown voltage and increased leakage current, degrading the quality of semiconductor devices.
Innovation Solution
A semiconductor device with stripe-shaped trenches and embedded semiconductor regions, where the regions are spaced uniformly to prevent cavity formation by ensuring consistent epitaxial growth and maintaining a fixed gap, thereby controlling the depletion layer extension and breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If deep trench embedding is performed with non-uniform distance from side surface, then manufacturing complexity is reduced, but cavity areas are formed in the drift region causing quality degradation
Solution Approach 1:
The patent applies preliminary action by forming a filler layer in the trenches before embedding the semiconductor layers. This filler layer pre-establishes a reference level that guides subsequent epitaxial growth, ensuring uniform embedding depth even when trench distances from side surfaces vary. The filler layer acts as a preparatory structure that prevents cavity formation by providing a baseline for consistent layer deposition across all trenches.
Solution Approach 2:
The filler layer serves as an intermediary element between the trench structure and the epitaxially grown semiconductor layers. It mediates the embedding process by providing a uniform reference surface that ensures consistent deposition of subsequent layers, thereby preventing cavity formation while accommodating variations in trench geometry without requiring perfect uniformity in the original trench formation.
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
The solution prevents cavity formation in the drift region, ensuring consistent breakdown voltage and reducing leakage current, thereby enhancing the quality and performance of semiconductor devices.
Implementation Method 1
embedding the deep trench by a conductivity type epitaxial layer different from the semiconductor substrate
Implementation Method 2
the semiconductor substrate and the plurality of the semiconductor regions are depleted by a depletion layer extended in the direction in parallel to the first principal surface from a plurality of pn junction interfaces
Data Source
AI summary
A semiconductor device includes: a first conductivity type semiconductor substrate; and a plurality of second conductivity type semiconductor regions, the respective second conductivity type semiconductor regions being embedded in a plurality of stripe shaped trenches formed in the semiconductor substrate so that the respective second conductivity type semiconductor regions are extended in the row direction or the column direction in parallel with a first principal surface of the semiconductor substrate and are spaced in a fixed gap mutually. The semiconductor substrate and the plurality of the semiconductor regions are depleted by a depletion layer extended in the direction in parallel to the first principal surface from a plurality of pn junction interfaces, and the respective pn junction interfaces are formed between the semiconductor substrate and the plurality of the semiconductor regions.