Buried Gate Liner Metal Alloy Gradient for Leakage Reduction
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Solution Overview
Problem
The increasing integration density and downsizing of semiconductor devices lead to higher interconnection resistance and increased leakage currents due to reduced gate electrode sizes, particularly between the gate electrode and the drain region.
Innovation Solution
A semiconductor device design featuring a buried gate structure with a liner that includes a metal alloy, where the second portion of the liner is closer to the source/drain region and has a higher concentration of implanted and/or diffused metal atoms, reducing resistance and leakage current by applying a metal alloy with a lower work function in the upper portion of the gate structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gate electrode size is reduced to increase integration density, then the integration density is improved, but the interconnection resistance increases
Solution Approach 1:
The liner is divided into two portions with different metal alloy concentrations: a first portion farther from the source/drain region and a second portion closer to the source/drain region. The second portion has a higher concentration of metal atoms, creating a gradient structure that optimizes both resistance and leakage current characteristics in different spatial locations.
Solution Approach 2:
The concentration of metal atoms in the liner is varied by position, with the second portion having a greater concentration of implanted and/or diffused metal atoms than the first portion. This parameter change allows optimization of electrical properties without changing the overall device dimensions.
2Productivity
If the gate electrode size is reduced to increase integration density, then the integration density is improved, but the leakage current increases
Solution Approach 1:
The liner structure uses different metal alloy concentrations in different portions to address leakage current specifically at the critical interface region near the source/drain, while maintaining overall device miniaturization for high integration density.
Solution Approach 2:
The liner is formed as a composite structure with a metal alloy that has a lower work function than polysilicon, combining materials with different properties to simultaneously reduce leakage current and maintain gate control in the scaled device.
3Object-generated harmful factors
If a metal alloy with lower work function is applied in the upper portion of the gate structure, then the leakage current is reduced, but the device complexity increases
Solution Approach 1:
The liner is segmented into two distinct portions with different metal alloy concentrations, allowing independent optimization of each region's properties to reduce leakage current while managing the complexity through systematic division rather than uniform modification.
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 the resistance of the gate electrode and leakage current, enhancing the electrical performance of the semiconductor device by minimizing the electric field applied between the gate and source/drain regions.
Implementation Method 1
applying a metal alloy with a lower work function in the upper portion of the gate structure
Implementation Method 2
the second portion may include a metal alloy... The second portion of the liner may include a first concentration of implanted and/or diffused metal atoms that is greater than a second concentration of the metal atoms in the first portion
Data Source
AI summary
Semiconductor devices are provided. A semiconductor device includes a substrate, and a source/drain region in the substrate. Moreover, the semiconductor device includes a gate structure in a recess in the substrate. The gate structure includes a liner that includes a first portion and a second portion on the first portion. The second portion is closer, than the first portion, to the source/drain region. The second portion includes a metal alloy. Methods of forming a semiconductor device are also provided.