FinFET with Multi-Threshold Fins for RF Gain
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Solution Overview
Problem
Fin field effect transistors (finFETs) face challenges in achieving high gain over a wide band and low distortion characteristics, which are essential for high-frequency applications.
Innovation Solution
The semiconductor device incorporates multiple fins with distinct threshold voltages by varying their widths and doping concentrations, allowing for a finFET configuration where the first fin, second fins, and third fins have different threshold voltages, enhancing transconductance and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gate length is decreased for miniaturization, then the integration degree is enhanced, but the cut-off characteristic of the drain current deteriorates due to the punch-through phenomenon
Solution Approach 1:
The channel region is divided into multiple fins that protrude from the substrate surface. By segmenting the channel into multiple vertical fins, the effective channel width is increased without increasing the planar area, allowing miniaturization while maintaining good cut-off characteristics through the fin structure's ability to suppress punch-through phenomenon.
Solution Approach 2:
The channel is extended into the vertical dimension by forming fins that protrude from the substrate surface. This dimensional transition from planar to vertical channel structure allows for shorter gate lengths while maintaining effective channel control and suppressing short-channel effects.
2Power
If multiple fins are formed to increase drain current, then the maximum oscillation frequency and cut-off frequency are enhanced, but it becomes difficult to achieve high gain in a wide band with low distortion characteristic
Solution Approach 1:
Different fins are doped with different concentrations of impurity atoms, creating local variations in threshold voltage across the fin structure. This local quality differentiation allows each fin to operate at different bias conditions, enabling high gain in a wide band while reducing distortion through the combined output of fins with complementary characteristics.
Data Source
AI summary
A semiconductor device includes a fin field effect transistor configured to include at least a first fin and a second fin. Threshold voltage of the first fin and threshold voltage of the second fin are different from each other in the fin field effect transistor.