Semiconductor Device Trench Gate Leakage Reduction
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Solution Overview
Problem
Semiconductor devices with trench gate structures face a trade-off between reducing ON-resistance and switching loss, where lowering ON-resistance increases turn-off time and switching loss due to high carrier discharge.
Innovation Solution
The semiconductor device incorporates a specific structure with a p-type semiconductor layer, an n-type semiconductor layer, and a p-type semiconductor layer in the PNP region, along with a boundary portion of lower n-type impurity concentration, which reduces leakage currents and enhances carrier discharge efficiency during turn-off, thereby minimizing both ON-resistance and switching loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If gate electrodes extend deep into the n−-type base layer to reduce ON-resistance, then carrier accumulation efficiency improves and ON-resistance decreases, but turn-off time lengthens and switching loss increases
Solution Approach 1:
The patent applies local quality by creating a PNP region with specific doping characteristics (p-type semiconductor layer with first doping concentration, n-type semiconductor layer with second doping concentration, and p-type semiconductor layer with third doping concentration) in a localized area of the base layer. This localized structural modification enables efficient carrier discharge at the PNP region while maintaining deep gate electrode extension for low ON-resistance, thus resolving the contradiction between steady loss reduction and turn-off time reduction.
Data Source
AI summary
A semiconductor device includes a semiconductor body; a first electrode on the semiconductor body; control electrodes provided in the semiconductor body along the surface thereof; and first films electrically insulating the control electrodes from the semiconductor body. The semiconductor body includes first, third, sixth layers of a first conductivity type, and second, fourth, fifth layers of a second conductivity type. The second to sixth layers are provided between the first electrode and the first layer. The second and third layers are positioned between two adjacent control electrodes. The fourth to sixth layers are positioned between other two adjacent control electrodes. The sixth layer positioned between the fourth layer and the fifth layer. The sixth layer includes a major portion and a boundary portion between the major portion and one of the first films. An impurity concentration in the boundary portion is lower than that in the major portion.