Conductive Field Plate Layout for Edge Breakdown Control
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Solution Overview
Problem
The concentration of electric field at corners, tips, or edges of semiconductor device regions can lead to breakdown issues, limiting the breakdown voltage and reliability of semiconductor devices in high voltage applications.
Innovation Solution
Incorporating a conductive field plate over the edge of the active region and forming lightly doped wells to distribute the electric field uniformly, reducing the likelihood of excessive field concentration and enhancing breakdown voltage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor device structure is used, then the device is simple to manufacture, but the breakdown voltage is limited due to electric field concentration at edges and corners
Solution Approach 1:
A conductive field plate is introduced as an intermediary element between the gate and the active region edges. This field plate serves as a mediator to redistribute the electric field, preventing direct concentration at the vulnerable edge regions while maintaining the overall device structure
Solution Approach 2:
The field plate extends in a direction transverse to the gate length, adding a dimensional element that overlaps the active region edges. This transverse extension creates a new spatial dimension for electric field management, allowing the field to be distributed across a broader area rather than concentrating at sharp edges
2Reliability
If the device structure is modified to improve breakdown voltage, then the reliability increases, but the manufacturing process becomes more complex
Solution Approach 1:
The field plate is formed as an integrated part of the gate structure fabrication process. The same dielectric layer and conductive material deposition steps that create the gate are used to form the field plate, merging two functions into a unified manufacturing sequence rather than requiring separate processing steps
Solution Approach 2:
The gate structure serves dual functions: it provides the primary gate control over the active region and simultaneously acts as a field plate extending transverse to the gate length to protect the edges. This multi-functionality eliminates the need for separate field plate structures and their associated manufacturing complexity
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 solution effectively increases the breakdown voltage of semiconductor devices, improving their ability to withstand high gate voltages without damage or irregular current behavior, making them suitable for high voltage applications like power management ICs.
Implementation Method 1
The presence of a field plate and/or a lightly doped well results in an approximately uniform electric field distribution along the edge of the active region
Implementation Method 2
The presence of a field plate and/or a lightly doped well results in an approximately uniform electric field distribution along the edge of the active region
Data Source
AI summary
A semiconductor device includes an isolation structure in a substrate; and a gate structure over an active region of the substrate. The isolation structure surrounds the active region. The gate structure includes a first section parallel to a second section. The semiconductor device further includes a conductive field plate extending between the first section and the second section and overlapping an edge of the active region. A portion of the conductive field plate extends beyond the edge of the active region, The conductive field plate includes a dielectric layer having a first portion and a second portion, and the first portion is thicker than the second portion. The semiconductor device includes a first well overlapping the edge of the active region. The first well extends underneath the isolation structure. The conductive field plate extends beyond an outer-most edge of the first well.