Trench Gate Semiconductor Layout for Stable Body Potential
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Solution Overview
Problem
In semiconductor device manufacturing, the potential of the body region located on the outer peripheral side than the trench gate is unstable due to the high resistance of p-type regions, particularly in silicon carbide materials, leading to potential instability and increased resistance.
Innovation Solution
A semiconductor device design that includes a semiconductor layer with a drift region, a body region, a source region, a first contact region, and a second contact region, where the second contact region is located in the intermediate region and extends around the source region, stabilizing the body region's potential and allowing simultaneous formation with the first contact region without increasing process steps, thereby reducing manufacturing costs and stabilizing the body region's potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion implantation technique is used to form body region and source region, then semiconductor device can be manufactured, but the potential of the body region located on the outer peripheral side than the trench gate becomes unstable due to high resistance of p-type regions
Solution Approach 1:
The patent applies local quality by creating a contact region with higher impurity concentration specifically at the outer peripheral side of the active region where the body region is located. This localized modification of impurity concentration reduces the resistance of the p-type body region in the critical peripheral area, thereby stabilizing the potential without altering the overall device structure or requiring additional process steps.
Solution Approach 2:
The patent changes the impurity concentration parameter by forming a contact region with higher impurity concentration than the surrounding body region. This parameter change is achieved through selective ion implantation that modifies the electrical properties of the body region in the peripheral area, reducing resistance and stabilizing potential while maintaining the same manufacturing process flow.
2Reliability
If additional contact regions are formed to stabilize body region potential, then potential stability improves, but manufacturing process complexity and cost increase
Solution Approach 1:
The patent merges the formation of the contact region with the existing ion implantation process used to create the body region and source region. By incorporating the contact region formation into the same manufacturing step using the same ion implantation technique, the patent avoids adding separate process steps, thereby improving potential stability without increasing manufacturing process complexity or cost.
Solution Approach 2:
The ion implantation process is given multi-functionality by using it to form both the body region/source region and the contact region in a single process step. This universal application of the ion implantation technique allows the manufacturing process to achieve multiple objectives simultaneously, including potential stabilization, without requiring additional specialized processes.
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 semiconductor device achieves stable potential for the body region and reduces contact resistance, enabling efficient current control and low-cost manufacturing by matching impurity concentration profiles in the contact regions and stabilizing the body region's potential, thus addressing the instability issues.
Implementation Method 1
forming a contact region, which includes a first contact region and a second contact region, by implanting ions of second conductivity-type impurities toward the first main surface of the semiconductor layer through the second mask
Data Source
AI summary
A semiconductor layer in a semiconductor device includes a drift region of a first conductivity type, a body region of a second conductivity type disposed above the drift region, a source region of the first conductivity type disposed above the body region, and a first contact region and a second contact region each having a higher concentration of second conductivity-type impurities than the body region. The first contact region is located in an active region, and reaches the body region beyond the source region. The second contact region is located in an intermediate region, reaches the body region beyond the source region, and extends around the source region along a peripheral edge of the source region. Concentration distributions of the second conductivity-type impurities in a depth direction of the first contact region and the second contact region match with each other.