Metal Gate Stack Oxygen-Trapping Layers for Uniform Nitride Thickness
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Solution Overview
Problem
The challenge in semiconductor manufacturing lies in achieving uniformity and thickness control of metal compound layers, particularly metal nitride layers, as semiconductor devices continue to shrink, complicating the manufacturing process.
Innovation Solution
A method involving the formation of an oxygen-trapping layer, either nitrogen-rich (N-rich) or oxygen-rich (O-rich), prior to depositing a metal nitride layer, which enhances thickness and uniformity by reducing deposition duration while increasing the final thickness of the metal nitride layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to form metal nitride layers, then the deposition process can be completed, but the thickness uniformity is poor and gap-filling issues occur
Solution Approach 1:
An oxygen-trapping layer is formed prior to the metal nitride layer deposition. This preliminary layer traps oxygen that would otherwise interfere with the deposition process, enabling subsequent deposition to proceed with improved thickness uniformity and reduced gap-filling issues.
Solution Approach 2:
The oxygen-trapping layer acts as an intermediary between the substrate and the metal nitride layer. It mediates the interaction by capturing oxygen, thereby creating favorable conditions for uniform metal nitride deposition without direct oxygen interference.
2Quantity of substance
If deposition duration is extended to achieve sufficient thickness, then thicker metal nitride layers can be formed, but the deposition efficiency decreases and gap-filling issues worsen
Solution Approach 1:
The oxygen-trapping layer is formed in advance to remove oxygen interference before deposition. This allows the metal nitride layer to deposit more efficiently and uniformly, achieving sufficient thickness in shorter time without gap-filling problems.
Solution Approach 2:
The deposition process parameters are optimized by introducing the oxygen-trapping layer, which changes the deposition environment. This enables faster deposition rates and improved uniformity, achieving target thickness with higher efficiency.
3Reliability
If metal nitride layers are made thicker to improve device performance, then performance increases, but uniformity control becomes more difficult
Solution Approach 1:
The oxygen-trapping layer is prepared beforehand to eliminate oxygen interference throughout the deposition process. This enables formation of thicker metal nitride layers with maintained uniformity, as the trapping layer continuously manages oxygen during extended deposition.
Solution Approach 2:
The oxygen-trapping layer serves as a mediator that protects the metal nitride deposition from oxygen interference. This intermediary function becomes increasingly important as deposition thickness increases, maintaining uniformity throughout the thicker layer formation.
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
This approach improves the efficiency of film deposition, allows for thicker metal nitride layers with improved uniformity, and mitigates gap-filling issues, simplifying the fabrication process for semiconductor structures.
Implementation Method 1
an oxygen-trapping layer is formed over a substrate. An electron treatment is performed on the oxygen-trapping layer. A first metal nitride layer is formed over the oxygen-trapping layer
Implementation Method 2
An electron treatment is performed on the oxygen-trapping layer
Data Source
AI summary
A semiconductor structure includes a first FET device and a second FET device. The first FET device includes a first metal gate, and the second FET device includes a second metal gate. The first metal gate includes a first high-k gate dielectric layer, a first oxygen-trapping layer over the first high-k gate dielectric layer, and a first metal nitride layer over the first oxygen-trapping layer. The second metal gate includes a second high-k gate dielectric layer, a second oxygen-trapping layer over the second high-k gate dielectric layer, and a second metal nitride layer over the second oxygen-trapping layer. The first metal nitride layer and the second metal nitride layer include a same material. A thickness of the first metal nitride layer is different from a thickness of the second metal nitride layer.