FinFET Semiconductor Device With Ridge Body Region
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Solution Overview
Problem
Power transistors in automotive and industrial electronics require a balance between low on-state resistance and high voltage blocking capability, which existing semiconductor devices struggle to achieve effectively, especially in integrated circuits where components like switches and control circuits are integrated.
Innovation Solution
A semiconductor device comprising an array of field effect transistors with a source contact trench, drain contact trench, and gate electrode structures arranged in an alternating manner, where the body region is formed as a ridge extending between the source and drain regions, allowing for efficient control of conductivity and reduced leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the channel width is increased to reduce on-state resistance, then the device area increases
Solution Approach 1:
The patent transitions from a planar channel structure to a three-dimensional FinFET structure with vertical fins extending from the substrate. This dimensional change allows the channel width to be effectively increased through the vertical fin height while maintaining a compact lateral footprint, thereby reducing on-state resistance without proportionally increasing the device area.
Solution Approach 2:
The channel is segmented into multiple parallel fins rather than a single planar channel. This segmentation allows the total effective channel width to be summed across all fins, achieving low on-state resistance through cumulative conductive paths while keeping each fin's lateral dimension small, thus controlling overall device area.
2Speed
If the channel length is reduced to increase switching speed, then short channel effects increase
Solution Approach 1:
The FinFET structure introduces a vertical dimension to the channel, creating a three-dimensional conduction path. This allows for shorter lateral channel lengths that enable fast switching while the vertical fin structure provides enhanced gate control over the channel, suppressing short channel effects that would otherwise dominate in planar devices with short channels.
Solution Approach 2:
The gate structure wraps around the fin channel, providing localized and enhanced electric field control specifically at the channel region. This local quality improvement in gate control ensures that even with reduced channel length, the electric field distribution maintains proper carrier confinement and threshold voltage control, mitigating short channel effects.
3Reliability
If the voltage blocking capability is increased, then the device complexity increases
Solution Approach 1:
The vertical FinFET structure provides natural voltage blocking through the drain-to-substrate junction in the vertical direction. The fin height and doping profile in the vertical dimension create an efficient depletion region for voltage blocking, achieving high breakdown voltage capability without requiring complex lateral structures or additional blocking layers that would increase device complexity.
Data Source
AI summary
A semiconductor device comprises a field effect transistor in a semiconductor substrate having a first main surface. The field effect transistor comprises a source region, a drain region, a body region, and a gate electrode at the body region. The gate electrode is configured to control a conductivity of a channel formed in the body region, and the gate electrode is disposed in gate trenches. The body region is disposed along a first direction between the source region and the drain region, the first direction being parallel to the first main surface. The body region has a shape of a ridge extending along the first direction, the body region being adjacent to the source region and the drain region. The semiconductor device further comprises a source contact and a body contact, the source contact being electrically connected to a source terminal, the body contact being electrically connected to the source contact and to the body region.