Field Plate Gate Layout for Lower Parasitic Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radio frequency devices face challenges in achieving good gain characteristics at high frequencies due to parasitic capacitance, which is difficult to adjust without causing electrostatic breakdown when modifying the thickness or dielectric constant of dielectric layers.
Innovation Solution
A semiconductor device design with a first dielectric layer thicker in one area and thinner in another, combined with a gate structure and field plate configuration, reduces parasitic capacitance and adjusts electric field stresses, improving high-frequency gain characteristics without causing electrostatic breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness or dielectric constant of the dielectric layer is adjusted to reduce parasitic capacitance, then the gain characteristic at higher frequencies is improved, but electrostatic breakdown occurs
Solution Approach 1:
The first dielectric layer is designed with non-uniform thickness, being thicker in the first area under the second gate structure and thinner in the second area under the field plate. This local variation in dielectric thickness allows different regions to serve different functions: the thicker region reduces parasitic capacitance between the second gate structure and drain, while the thinner region maintains strong electric field control near the channel, preventing electrostatic breakdown.
Solution Approach 2:
The patent introduces a vertical dimension variation in the dielectric layer thickness profile. Instead of uniform thickness, the dielectric layer transitions from thicker to thinner regions vertically across the device structure. This dimensional change enables simultaneous optimization of capacitance reduction and electric field management without requiring material composition changes.
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 design effectively reduces parasitic capacitance and enhances the robustness of the device by managing electric field peaks, thereby improving the gain characteristics at higher frequencies while maintaining device reliability.
Implementation Method 1
the capacitance between the second gate structure and a drain is reduced due to a large thickness of the first dielectric layer in the first area
Implementation Method 2
this design may further re-adjust electric field stresses inside the device. Because the thickness of the first dielectric layer in the first area is large, an electric field peak at the second gate structure is reduced
Data Source
AI summary
A semiconductor device includes a substrate, a gate, a second dielectric layer, and a field plate. The substrate has a first dielectric layer, and a thickness of the first dielectric layer in a first area is greater than a thickness of the first dielectric layer in a second area outside the first area. The gate is located on the substrate and in the first area, the gate includes a first gate structure and a second gate structure, and the second gate structure is formed on a side of the first dielectric layer that is away from the substrate and covers a part of the first dielectric layer. The second dielectric layer covers the gate and the first dielectric layer. The field plate is located on the second dielectric layer and is disposed in both the first area and the second area.