Power Semiconductor Gate Trench Insulation for Avalanche Breakdown
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Solution Overview
Problem
The existing semiconductor power devices, such as Schottky barrier diodes and transistors, face insulation breakdown issues due to high electric fields concentrating at the oxide film during avalanche breakdown, leading to reduced avalanche resistance.
Innovation Solution
Incorporating a high dielectric-constant portion in the insulation film contiguous to the breakdown voltage holding layer, which reduces the electric field strength and enhances insulation film durability by using materials like SiN, Al2O3, or AlON, and forming trench or planar gate structures with high dielectric-constant materials at critical areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxide film (SiO2) is used as the insulation film in Schottky barrier diodes and transistors, then the device structure is simple and manufacturing is easy, but the insulation film breaks down under high electric fields during avalanche breakdown, reducing avalanche resistance
Solution Approach 1:
The patent applies composite materials by combining high dielectric-constant materials (such as silicon nitride SiN, aluminum oxide Al2O3, or aluminum oxynitride AlON) with traditional oxide films to create a multi-layer insulation film structure. This composite structure provides both high breakdown voltage resistance and adequate insulation performance, resolving the contradiction between reliability and material simplicity.
Solution Approach 2:
The patent implements local quality by placing high dielectric-constant materials specifically at critical regions where high electric fields concentrate during avalanche breakdown, such as at the edges of the semiconductor substrate or at interfaces with metal electrodes. This localized approach enhances avalanche resistance precisely where needed without requiring complete restructuring of the entire insulation film.
2Reliability
If the insulation film is made of high dielectric-constant materials to reduce electric field strength, then withstanding voltage increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes parameter changes by selecting high dielectric-constant materials that inherently provide lower electric field strength for the same voltage stress. This material parameter change allows the insulation film to withstand higher voltages while maintaining acceptable manufacturing tolerances, as the higher dielectric constant provides a margin of safety against field-induced breakdown.
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 high dielectric-constant materials effectively mitigate insulation breakdown, allowing for higher withstanding voltage and lower on-resistance in semiconductor power devices, particularly in Schottky barrier diodes and field-effect transistors.
Implementation Method 1
an insulation film that is formed on the breakdown voltage holding layer and that has a high dielectric-constant portion having a higher dielectric constant than SiO2 at a part contiguous to the breakdown voltage holding layer
Data Source
AI summary
A method for producing a semiconductor power device includes forming a gate trench from a surface of the semiconductor layer toward an inside thereof. A first insulation film is formed on the inner surface of the gate trench. The method also includes removing a part on a bottom surface of the gate trench in the first insulation film. A second insulation film having a dielectric constant higher than SiO2 is formed in such a way as to cover the bottom surface of the gate trench exposed by removing the first insulation film.