RF Device Segmented Wells for Frequency Response
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Solution Overview
Problem
Conventional high-voltage radio frequency devices achieve high output impedance and breakdown voltage but fail to effectively improve frequency response due to an excessively large gate area.
Innovation Solution
The proposed radio frequency device incorporates a substrate with a well of the first type and a well of the second type, where a gate of the first type is formed over the second well, and a dummy gate of the first type is formed over the first well, with doped regions and source/drain regions strategically placed to optimize frequency response while maintaining high impedance and voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate area is increased to achieve high output impedance and breakdown voltage, then the output impedance and breakdown voltage are improved, but the frequency response deteriorates
Solution Approach 1:
The device is divided into two separate wells (first type and second type) with different gate structures. The first well with dummy gate handles high voltage requirements, while the second well with real gate handles frequency response requirements, segmenting the conflicting functions into separate physical regions.
Solution Approach 2:
Different regions of the device are given different properties: the first well region is optimized for high breakdown voltage with dummy gates and specific doping, while the second well region is optimized for frequency response with proper gate control, allowing each local region to excel at its specific function.
2Reliability
If the gate area is increased to achieve high output impedance, then the output impedance is improved, but the frequency response deteriorates
Solution Approach 1:
The gate control function is segmented from the high voltage withstand function. The second well with gate provides the necessary output impedance characteristics, while the first well with dummy gate provides high voltage capability, separating the two conflicting requirements into distinct functional zones.
Solution Approach 2:
The dummy gate structure acts as an intermediary that provides high voltage capability without the harmful effect of large gate area on frequency response. It mediates between the need for high output impedance and the need for good frequency response by providing voltage blocking without signal control.
Data Source
AI summary
A radio frequency (RF) device that can achieve high frequency response while maintaining high output impedance and high breakdown voltage includes a substrate, a gate, at least a dummy gate, at least a doped region, a source region and a drain region. The substrate includes a well of first type and a well of second type. The well of second type is adjacent to the well of first type.