Needle-Shaped Field Plate Structures for Semiconductor Devices
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Solution Overview
Problem
Existing semiconductor devices with stripe-shaped field electrodes face challenges in achieving high dopant concentrations in the drift portion without compromising blocking capability, and they have high parasitic capacitances and on-state resistance.
Innovation Solution
The use of needle-shaped first and second field plate structures that extend into the semiconductor die, forming a grid-like gate structure, which increases the total channel width per unit area and reduces parasitic capacitances, while maintaining high dopant concentrations and blocking capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If stripe-shaped field electrode structures are used, then the device structure is simple, but the parasitic capacitances and on-state resistance are high
Solution Approach 1:
The field electrode structure is segmented into multiple needle-shaped field plate structures arranged in a grid pattern, replacing the conventional stripe-shaped continuous structure. This segmentation reduces the overlapping area between field electrodes and drift region, thereby reducing parasitic capacitances while maintaining electrical field control effectiveness.
Solution Approach 2:
The field electrode structure transitions from a two-dimensional stripe pattern to a three-dimensional needle-shaped configuration extending vertically into the semiconductor substrate. This dimensional change allows for reduced parasitic capacitance by minimizing the lateral overlap area while maintaining the vertical electric field control function.
2Reliability
If needle-shaped field plate structures are used, then parasitic capacitances are reduced, but the device complexity increases
Solution Approach 1:
The field electrode is segmented into multiple discrete needle-shaped structures arranged in a regular grid pattern. While this increases structural complexity compared to a continuous stripe, the regular pattern allows for standardized manufacturing processes and predictable electrical characteristics, making the complexity manageable and beneficial for performance.
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 enhances the semiconductor device's performance by reducing on-state resistance and maintaining high blocking capability, while also minimizing parasitic capacitances, leading to improved reliability and efficiency.
Implementation Method 1
field plate structures extending from one side into the semiconductor die deplete a drift portion of the semiconductor die
Implementation Method 2
Shrinking the field plate structures to needle-shaped field plate structures facilitates a grid-like gate structure between the field plate structures, wherein the grid-like gate structure provides a larger total channel width per unit area
Data Source
AI summary
A semiconductor device includes a transistor cell region, and a first termination region devoid of transistor cells. The transistor cell region includes a gate structure, a plurality of needle-shaped first field plate structures, body regions of a second conductivity type, and source regions of a first conductivity type. The first termination region surrounds the transistor cell region and includes needle-shaped second field plate structures. The needle-shaped first field plate structures are arranged in a first pattern and the needle-shaped second field plate structures are arranged in a second pattern.