Multi-Gate Spacer Geometry for Leakage-Resistant Gate Trenches
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Solution Overview
Problem
As semiconductor devices become more highly integrated, they face increased reliability issues due to leakage currents, which reduce their performance and longevity, particularly in multi-gate transistors where the short channel effect and current control are challenging to manage.
Innovation Solution
A semiconductor device design featuring a substrate with a gate structure and spacers where the upper surface of the gate electrode is convex and the spacer is concave, allowing for improved etching processes that reduce leakage currents by maintaining a sufficient distance between the gate electrode and contacts, thereby enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate length is increased to improve current control capability, then the current control capability is improved, but the device area increases
Solution Approach 1:
The patent transitions from a planar gate structure to a three-dimensional multi-gate structure (such as FinFET or nanosheet configurations). By utilizing vertical dimensions and multiple gate surfaces, the effective gate control area is increased without proportionally increasing the planar device footprint, thereby improving current control while maintaining compact area.
Solution Approach 2:
The gate structure is configured to wrap around or enclose the channel region from multiple sides (top, bottom, and sidewalls), creating a nested configuration where the gate surrounds the channel. This multi-gate configuration enhances control over the channel current without requiring a proportional increase in the overall device area.
2Productivity
If the semiconductor device is highly integrated to increase density, then the device density is improved, but leakage current increases
Solution Approach 1:
The patent introduces a spacer structure formed before the gate electrode that creates a controlled offset between the gate and contact regions. This preliminary structural arrangement prevents direct alignment that would cause leakage, ensuring that even as devices are scaled and integrated at higher densities, the leakage current is suppressed by the pre-established geometric separation.
Solution Approach 2:
The spacer structure creates a localized geometric feature at the gate-contact interface that specifically addresses leakage current without affecting the overall device performance. By modifying only the critical interface region where leakage occurs, the patent enables high-density integration while maintaining low leakage through localized structural optimization.
3Ease of manufacture
If the gate structure is formed with standard planar configuration, then the manufacturing process is simple, but the short channel effect is not effectively suppressed
Solution Approach 1:
The patent extends the gate structure into the vertical dimension, creating multi-gate configurations (FinFET, nanosheets) that wrap around the channel. This three-dimensional configuration provides superior electrostatic control over the channel, effectively suppressing short channel effects while remaining compatible with existing semiconductor manufacturing processes through adapted deposition and etching steps.
4Area of stationary object
If the contact is positioned close to the gate electrode to reduce area, then the device area is reduced, but leakage current and magnetic field effects increase
Solution Approach 1:
The spacer structure serves as an intermediary element between the gate electrode and the contact. It creates a controlled geometric offset that maintains an effective distance between these components, preventing direct alignment that would cause leakage current and magnetic field interference, while still allowing the contact to be positioned relatively close to the gate for area efficiency.
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 leakage currents and improves the reliability of semiconductor devices by maintaining a greater distance between the gate electrode and contacts, preventing strong magnetic fields and ensuring better current control, thus addressing the short channel effect and enhancing overall device performance.
Implementation Method 1
performing a first etching process having a larger etching rate with respect to the gate structure than the spacer, and after performing the first etching process, performing a second etching process having a larger etching rate with respect to the spacer than the gate structure
Data Source
AI summary
A semiconductor device with improved reliability and a method for fabricating the same are provided. The semiconductor device includes a substrate, a first spacer defining a gate trench on the substrate, and a gate electrode in the gate trench, wherein a height of an upper surface of the gate electrode adjacent to the first spacer increases in a direction away from the first spacer.