Termination Trench Doping Layout for Power Transistor Breakdown Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power semiconductor transistors face challenges in designing a termination region that supports breakdown voltage while accommodating a blanket implanted body region, complicating the transition of high potential to low potential near the edge of the semiconductor substrate.
Innovation Solution
A termination region design featuring termination trenches that surround active cell regions, with a doped region of the same conductivity type as the body region, extending deeper into the substrate and offset from the trench centerline, to support breakdown voltage and facilitate potential transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a blanket implant is used to form the body region, then the body region can be uniformly formed across the substrate, but the termination region design becomes complicated and cannot effectively support breakdown voltage
Solution Approach 1:
The termination region is segmented into multiple functional zones: a first termination region with a first doped region extending deeper than the body region, and a second termination region with a second doped region at a different depth. This segmentation allows each zone to independently contribute to breakdown voltage support, resolving the contradiction by maintaining blanket implant simplicity while achieving reliable voltage support through structured doping profiles.
Solution Approach 2:
Different doped regions are created with specific local properties: the first doped region extends deeper into the substrate in the first termination region, while the second doped region is positioned at a different depth in the second termination region. These localized doping variations enable the termination region to effectively support breakdown voltage without complicating the overall blanket implant process.
2Reliability
If the termination region is designed to support high breakdown voltage, then electrical performance improves, but the transition of high potential to low potential becomes more complex
Solution Approach 1:
The potential transition is segmented into distinct stages by dividing the termination region into a first termination region and a second termination region, each with differently positioned doped regions. This creates a stepped potential gradient that facilitates smooth transition from high to low potential while maintaining high breakdown voltage support, avoiding the need for a single complex transition structure.
Solution Approach 2:
The doped regions are positioned at different vertical depths within the substrate rather than only lateral variations. The first doped region extends deeper than the body region while the second doped region is at a different depth, creating a three-dimensional doping architecture that enables effective potential transition and voltage support without increasing lateral structural complexity.
3Reliability
If the termination region provides effective potential transition, then electrical performance improves, but field concentration at the substrate edge increases
Solution Approach 1:
Doped regions are strategically positioned at different vertical locations within the termination region to create localized electric field management. The first doped region extends deeper than the body region while the second doped region is positioned at a different depth, creating a distributed field control structure that enables effective potential transition while dispersing and reducing field concentration at the substrate edge.
Solution Approach 2:
The termination region acts as an intermediary zone between the high-field active region and the low-field substrate edge. By incorporating doped regions at different depths, the termination region provides a gradual potential transition that mediates the electric field distribution, enabling effective potential transition while reducing harmful field concentration at the substrate edge through distributed field control.
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 design effectively supports breakdown voltage and transitions high potential to low potential, improving electrical performance and reducing potential field concentration at the substrate edge.
Implementation Method 1
The termination region must support the breakdown voltage of the transistor device while also providing a lateral transition of the high potential near the edge of the semiconductor substrate to a low potential in each active cell region
Data Source
AI summary
A transistor device includes: a semiconductor substrate having a termination region interposed between a first active cell region and an edge of the semiconductor substrate; and transistor cells in the first active cell region, each transistor cell including a gate trench formed in a body region of a first conductivity type. The body region extends into the termination region. The termination region includes: a first termination trench laterally surrounding the first active cell region and extending through the body region so that the body region is interrupted in the termination region by the first termination trench; and a first doped region of the first conductivity type that follows the first termination trench and adjoins part of a bottom of the first termination trench. The first doped region terminates deeper in the semiconductor substrate than the body region and is off-center to a longitudinal centerline of the first termination trench.