Field-Plate Semiconductor Structure for Higher Breakdown Voltage
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Solution Overview
Problem
Existing power semiconductor devices face challenges in achieving high breakdown voltages, high electron mobility, and good thermal stability, which are crucial for applications in wireless communications and electric vehicles.
Innovation Solution
A semiconductor structure is designed with a gate structure, a first and second dielectric layer separated by an etch stop layer, and a field plate with specific distance variations, redistributing electric fields to enhance breakdown voltage and electron mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor structures are used, then manufacturing is simpler, but breakdown voltage is insufficient
Solution Approach 1:
The dielectric structure is segmented into multiple layers (first dielectric layer, etch stop layer, second dielectric layer) with different functions. The field plate is divided into multiple portions (first, second, third, fourth portions) positioned at different heights and locations to independently control electric field distribution in different regions, thereby achieving high breakdown voltage through structured segmentation.
Solution Approach 2:
The patent introduces vertical dimensionality by positioning field plate portions at different heights above the semiconductor layer. The first field plate portion is at a higher position than the second field plate portion, creating a three-dimensional electric field control structure that enhances breakdown voltage without increasing planar footprint.
2Reliability
If field plate distance is uniform, then manufacturing is easier, but electron mobility is reduced due to electric field concentration
Solution Approach 1:
Different portions of the field plate are positioned at different distances from the semiconductor layer to create locally optimized electric field distribution. The second field plate portion is positioned closer to the semiconductor layer than the first field plate portion, allowing local enhancement of electron mobility where needed while maintaining overall device reliability.
3Reliability
If dielectric layers are directly stacked, then manufacturing steps are reduced, but electric field distribution is uncontrolled leading to current leakage
Solution Approach 1:
The etch stop layer serves as an intermediary between the first dielectric layer and the second dielectric layer. This intermediate layer enables precise control of the vertical position and thickness of the second dielectric layer, allowing accurate positioning of field plate portions to optimize electric field distribution and prevent current leakage through the interface region.
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 structure achieves high breakdown voltages, reduces current leakage, and maintains high electron mobility while ensuring thermal stability, suitable for high-power semiconductor components.
Implementation Method 1
A first distance between a lower surface of the first field plate portion and the semiconductor layer is larger than a second distance between a lower surface of the second field plate portion and the semiconductor layer, and a third distance between a lower surface of the third field plate portion and the semiconductor layer is smaller than a fourth distance between a lower surface of the fourth field plate portion and the semiconductor layer
Data Source
AI summary
A semiconductor structure includes a gate structure on a semiconductor layer on a substrate; a first dielectric layer continuously extending on the gate structure and the semiconductor layer and including a third portion and a fourth portion on an upper surface of the gate structure, a first portion, and a second portion; a second dielectric layer on an etch stop layer on at least the first portion and the fourth portion; and a field-plate. The field-plate includes a first field-plate portion and a fourth field-plate portion on the second dielectric layer and includes a second field-plate portion and a third field-plate portion on the second portion and the fourth portion, respectively. Lower surfaces of the first field-plate portion and the fourth field-plate portion are farther away from the semiconductor layer compared to lower surfaces of the second field-plate portion and the third field-plate portion, respectively.