Nitrogen-Doped Gate Dielectric for Low-Leakage FinFET Reliability
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Solution Overview
Problem
As integrated circuits (ICs) shrink in size, optimizing threshold voltages and minimizing leakage current becomes increasingly challenging, affecting performance and reliability due to the reduction in gate dielectric thickness.
Innovation Solution
Introducing a proper amount of nitrogen into the gate dielectric via an annealing operation to reduce leakage current and improve device reliability, using methods such as annealing in an active nitrogen atmosphere or forming capping layers to control nitrogen distribution and passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate dielectric thickness is reduced to increase functional density, then productivity is improved, but leakage current increases and reliability deteriorates
Solution Approach 1:
The patent introduces nitrogen into the gate dielectric layer to change its physical and electrical parameters. This modification allows the dielectric to maintain lower leakage current while keeping the thickness reduced, thus resolving the contradiction between productivity (through thinning) and reliability (through leakage reduction).
Solution Approach 2:
The patent creates a composite gate dielectric structure by incorporating nitrogen into the dielectric material. This composite approach enables the material to simultaneously achieve low leakage current and thin thickness, addressing both the productivity and reliability requirements.
2Productivity
If gate dielectric thickness is reduced to increase functional density, then productivity is improved, but threshold voltage uniformity deteriorates
Solution Approach 1:
Nitrogen introduction modifies the dielectric's electrical parameters, enabling better control over threshold voltage characteristics. This parameter change helps maintain uniform threshold voltage across the device even when the dielectric thickness is reduced for higher functional density.
3Reliability
If nitrogen is introduced into gate dielectric to reduce leakage current, then reliability is improved, but device complexity increases
Solution Approach 1:
The nitrogen introduction is performed as a preliminary annealing treatment before final device assembly. This preliminary action simplifies the overall process by addressing the leakage current issue early in the fabrication sequence, avoiding the need for additional complex mitigation steps later.
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 introduction of nitrogen into the gate dielectric effectively reduces leakage current and improves threshold voltage uniformity, enhancing the reliability and performance of IC devices while maintaining optimal p-type device characteristics.
Implementation Method 1
The gate dielectric layer includes nitrogen element
Implementation Method 2
annealing the semiconductor workpiece in an active nitrogen atmosphere
Data Source
AI summary
A device includes a semiconductor substrate, a fin structure on the semiconductor substrate, a gate structure on the fin structure, and a pair of source/drain features on both sides of the gate structure. The gate structure includes an interfacial layer on the fin structure, a gate dielectric layer on the interfacial layer, and a gate electrode layer of a conductive material on and directly contacting the gate dielectric layer. The gate dielectric layer includes nitrogen element.