Trench Gate Semiconductor Switching Element Field Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switching elements face challenges in alleviating electric field concentration around the corners of trenches in a long direction, which affects voltage resistance.
Innovation Solution
The switching element incorporates a semiconductor substrate with trenches, a gate insulation layer, and a gate electrode, featuring a bottom region with a low concentration region and a high concentration region, where the high concentration region has a higher impurity concentration than the low concentration region, to control depletion layer expansion and equipotential line distribution, thereby reducing electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trench structure is provided in the semiconductor substrate, then the switching element can control the depletion layer expansion and improve switching performance, but electric field concentration occurs around the corner of the trench in the long direction, reducing voltage resistance
Solution Approach 1:
The bottom region is divided into a low concentration region at the corner and a high concentration region adjacent to it. This local differentiation of impurity concentration allows the corner area to have different electrical properties than the rest of the bottom region, specifically reducing electric field concentration at the corner while maintaining proper depletion layer control in other areas.
Solution Approach 2:
The impurity concentration parameter is changed spatially within the bottom region. By creating a low concentration region with reduced impurity content at the corner position, the electrical characteristics at that location are modified to reduce electric field concentration, while the high concentration region maintains the necessary depletion layer control.
2Ease of manufacture
If the bottom region has uniform impurity concentration, then the manufacturing process is simpler, but electric field concentration occurs around the trench corner leading to insulation property deterioration
Solution Approach 1:
Instead of uniform impurity concentration throughout the bottom region, a local quality approach is taken by creating a low concentration region specifically at the corner position. This localized modification targets the problematic area without requiring complete restructuring of the entire bottom region, balancing manufacturing complexity with reliability improvement.
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
This configuration effectively suppresses electric field concentration around the corners, enhancing voltage resistance and reducing the risk of insulation property deterioration.
Implementation Method 1
When the switching element turns off, a depletion layer expands from an interface between the body region and the drift region. At this occasion, a depletion layer expands from an interface between the bottom region and the drift region as well.
Implementation Method 2
Due to this, the equipotential lines curve around a corner between the bottom surface of the trench and a side surface thereof. As a result, intervals between the equipotential lines become locally narrow around the corner. Due to this, an electric field concentration occurs around the corner.
Data Source
AI summary
A trench gate semiconductor switching element is provided. The semiconductor substrate of this element includes a second conductivity type bottom region in contact with the gate insulation layer at a bottom surface of the trench; and a first conductivity type second semiconductor region extending from a position in contact with a lower surface of the body region to a position in contact with a lower surface of the bottom region, and in contact with the gate insulation layer on a lower side of the body region. The bottom region includes a low concentration region in contact with the gate insulation layer in a first range of the bottom surface positioned at an end in a long direction of the trench; and a high concentration region in contact with the gate insulation layer in a second range of the bottom surface adjacent to the first range.