Trench Termination Structure for Semiconductor Devices
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Solution Overview
Problem
The existing termination structures for trench field effect transistors require complex photomask processes, limiting yield and production capacity, and are not suitable for miniaturization due to their large area, which affects the voltage sustaining capability of power semiconductor devices.
Innovation Solution
A termination structure for semiconductor devices is developed, featuring trenches with dielectric and conductive layers in a voltage-sustaining epitaxy region, where the dielectric layers are connected to increase breakdown voltage in a smaller area, and the conductive layer is electronically connected to both the active and termination areas, reducing the number of photomask processes required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large area termination structure is used to increase breakdown voltage, then the breakdown voltage is improved, but the device area increases which contradicts the miniaturization trend
Solution Approach 1:
The patent transitions from a planar termination structure to a three-dimensional trench structure. By etching trenches into the semiconductor substrate and filling them with dielectric material, the termination function is extended into the vertical dimension. This allows the breakdown voltage to be increased without proportionally increasing the surface area, as the voltage sustaining capability is achieved through the depth and geometry of the trenches rather than just the lateral footprint.
Solution Approach 2:
The termination structure is segmented into multiple parallel trenches rather than using a single large continuous structure. This segmentation allows the termination function to be distributed across multiple smaller units, achieving the required breakdown voltage through the collective effect of multiple trenches while maintaining a compact overall footprint.
2Reliability
If complicated photomask processes are used to manufacture trench field effect transistor, then the device performance is improved, but the processing time increases and yield is limited
Solution Approach 1:
The patent merges multiple photomask processes into a single integrated process flow. By designing the trench structure and termination region to be formed simultaneously through one photomask pattern, the need for separate masking steps is eliminated. This consolidation maintains the required device performance while significantly reducing processing time and the associated risk of yield loss from multiple process steps.
Solution Approach 2:
The single photomask process serves multiple functions: it defines both the trench geometry and the termination region configuration. This multi-functional approach eliminates the need for separate specialized photomask steps, reducing overall processing complexity and time while achieving the same device performance outcomes.
Data Source
AI summary
A termination structure of a semiconductor device is provided. The semiconductor device includes an active area and a termination area adjacent to the active area, in which the termination area has the termination structure. The termination structure includes a substrate, an epitaxy layer, a dielectric layer, a conductive material layer and a conductive layer. The epitaxy layer is disposed on the substrate and has a voltage-sustaining region. The voltage-sustaining region has trenches parallel to each other. The dielectric layer is disposed in the trenches and on a portion of the epitaxy layer. The conductive material layer is disposed on the dielectric layer in the trenches. The conductive layer covers the trenches, and is in contact with the conductive material layer and a portion of the epitaxy layer, and is electrically connected between the active area and the termination area. A method for manufacturing the termination structure is also provided.