Trench Semiconductor Structure for Low On-Resistance and Breakdown Voltage
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Solution Overview
Problem
Current semiconductor devices, such as insulated gate bipolar transistors (IGBTs), face challenges in minimizing on-resistance and increasing breakdown voltage, particularly with miniaturization leading to increased Miller capacitance and electric field concentration at trench bottoms.
Innovation Solution
The semiconductor device incorporates a drift layer with specific impurity concentration regions and column regions at the bottom of trenches, reducing electric field concentration and limiting Miller capacitance expansion, thereby enhancing breakdown voltage and decreasing on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If miniaturization is implemented to increase integration density, then productivity and integration are improved, but Miller capacitance increases and breakdown voltage decreases
Solution Approach 1:
The patent applies local quality by creating column regions with different impurity concentrations at specific locations (bottom portions of trenches) rather than uniformly across the entire drift layer. This localized modification allows the device to maintain low on-resistance in miniaturized configurations while preserving breakdown voltage through targeted electric field management at critical stress points.
Solution Approach 2:
The patent changes physical parameters by introducing column regions with controlled impurity concentrations (different from the drift layer) at the bottom portions of trenches. This parameter modification alters the electric field distribution and capacitance characteristics, enabling the device to achieve both low on-resistance and high breakdown voltage despite miniaturization.
2Reliability
If drift layer depth is increased to improve breakdown voltage, then reliability is improved, but device area increases reducing integration density
Solution Approach 1:
The patent enables thinner drift layers to achieve the same breakdown voltage by introducing column regions with specific impurity concentrations at the trench bottom portions. This localized modification allows the drift layer to be shallower (reducing device area) while maintaining adequate breakdown voltage through improved electric field distribution at critical locations.
Data Source
AI summary
This semiconductor device includes: an n-type drift layer; a p-type base region; a trench extending in the depth direction so as to pass through the base region and reach the drift layer; an insulating film formed on an inner surface of the trench; a gate trench surrounding the insulating film; and a p-type column region provided on the drift layer at a position at the bottom of the trench. The drift layer includes: a first region having a first concentration peak; and a second region that is provided at a position deeper than the trench and corresponding to the column region, and has a second concentration peak lower than the first concentration peak.