Super-junction Semiconductor Device with Loop-shaped Field Plate
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Solution Overview
Problem
Conventional super junction transistor devices face challenges in fabricating loop-shaped p-type doped regions, leading to non-uniform impurity concentrations and lower withstand voltage due to difficulties in controlling implant concentration at corner regions, resulting in increased on-resistance and reduced breakdown voltage.
Innovation Solution
The design features p-type doped regions in a stripe shape extending to the termination region, combined with a main loop-shaped field plate covering the second ending portion of a lightly-doped region, which improves the uniformity of epitaxy and reduces electric field strength, thereby enhancing the breakdown voltage and simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If loop-shaped p-type doped regions are formed in the termination region, then the breakdown voltage can be improved, but the fabrication process becomes complex and implant concentration control at corner regions becomes difficult
Solution Approach 1:
The p-type doped regions are divided into two distinct types: stripe-shaped p-type doped regions in the cell region and corner p-type doped regions at the termination region corners. This segmentation allows each type to be optimized independently - the stripe-shaped regions provide uniform impurity concentration through simple epitaxial growth, while the corner regions specifically address breakdown voltage enhancement at critical points.
Solution Approach 2:
Different regions of the device are given different doped region configurations tailored to their specific functional requirements. The cell region uses stripe-shaped p-type doped regions for uniformity and ease of fabrication, while the termination region corners use corner p-type doped regions specifically positioned to enhance breakdown voltage at these high-stress locations.
2Reliability
If loop-shaped p-type doped regions are formed in the termination region, then the breakdown voltage can be improved, but the on-resistance increases due to non-uniform impurity concentrations
Solution Approach 1:
The p-type doped regions are divided into two distinct types: stripe-shaped p-type doped regions in the cell region and corner p-type doped regions at the termination region corners. This segmentation allows each type to be optimized independently - the stripe-shaped regions provide uniform impurity concentration through simple epitaxial growth, while the corner regions specifically address breakdown voltage enhancement at critical points.
Solution Approach 2:
Multiple stripe-shaped p-type doped regions are arranged in a periodic pattern throughout the cell region, creating a uniform array that consistently provides the desired electrical characteristics. This regular repetition ensures uniform impurity concentration distribution and predictable device performance across the entire structure.
3Ease of manufacture
If stripe-shaped p-type doped regions extend to the termination region, then the fabrication process is simplified and epitaxy uniformity is improved, but additional field plate structures are needed to maintain breakdown voltage
Solution Approach 1:
The stripe-shaped p-type doped regions extend from the cell region into the termination region, merging the functions of cell region current conduction and termination region breakdown voltage enhancement into a single continuous structure. This eliminates the need for separate loop-shaped p-type doped regions and simplifies the fabrication process while maintaining electrical performance.
Solution Approach 2:
The lightly-doped region acts as an intermediary structure between the stripe-shaped p-type doped regions and the surface, providing gradual field termination and enhancing breakdown voltage. The loop-shaped field plate further mediates the electric field distribution at the device periphery, allowing the use of simpler stripe-shaped doped regions while maintaining high breakdown voltage.
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 improves the breakdown voltage and reduces the complexity of the fabrication process, achieving higher uniformity and reliability in the super junction semiconductor device by eliminating the need for curved lattice plane considerations and ensuring uniform impurity concentrations.
Implementation Method 1
by making the main loop-shaped field plate cover the second ending portion of the lightly-doped region to decrease the electric field strength generated at the second ending portion
Implementation Method 2
The drift layer includes a plurality of n-type doped regions and a plurality of p-type doped regions extending from the surface toward the substrate and arranged alternately to form a super-junction structure
Data Source
AI summary
A super junction semiconductor device is provided. The super-junction semiconductor device includes a substrate, a drift layer disposed on the substrate, an insulating layer, a lightly-doped region, and a main loop-shaped field plate. The drift layer includes a plurality of n- and p-type doped regions alternately arranged in parallel to form a super-junction structure, and defines a cell region and a termination region surrounding the cell region. The lightly-doped region is formed in the drift layer and connected to a surface of the drift layer. The lightly-doped region has a first end portion closer to the cell region and a second end portion farther away from the cell region. The insulating layer disposed on the drift layer covers the termination region. The main loop-shaped field plate is disposed on the insulating layer and covers the second end portion.