Semiconductor Gate Structure Void Filling via Atomic Diffusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The fabrication processes for semiconductor devices face challenges in adjusting threshold voltages of transistors, as the performance of work function layers is adversely affected due to insufficient blocking ability of thin first and barrier gate layers, leading to difficulties in forming subsequent layers and affecting device conductivity and resistance.
Innovation Solution
A method involving the formation of a first gate layer with a void, followed by a second gate layer with a smaller atomic radius material, and a thermal annealing process to fill the void, enhancing the conductivity and interface states between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a thin first gate layer is used to adjust threshold voltage, then the threshold voltage adjustment capability is improved, but the blocking ability is insufficient leading to poor interface states
Solution Approach 1:
The gate structure is divided into multiple segments: a first gate layer (e.g., titanium layer) and a second gate layer (e.g., aluminum layer). The first gate layer provides interface quality and blocking ability, while the second gate layer provides conductivity and threshold voltage adjustment capability. This segmentation allows each layer to specialize in different functions, resolving the contradiction between thin-layer threshold adjustment and sufficient blocking ability.
Solution Approach 2:
The gate structure uses composite materials by combining different metal layers with distinct properties. The first gate layer uses materials with good interface states (like titanium), while the second gate layer uses materials with high conductivity (like aluminum). This composite approach enables the overall structure to achieve both blocking ability and threshold voltage adjustment capability that single materials cannot provide alone.
2Manufacturing precision
If the first gate layer is made thinner to improve threshold voltage control, then the threshold voltage precision is improved, but voids form in the layer reducing reliability
Solution Approach 1:
The first gate layer is formed with controlled thickness and specific material properties before the second gate layer is deposited. This preliminary formation ensures the first gate layer has optimal interface states and blocking ability from the start, preventing void formation issues before they occur during subsequent processing.
Solution Approach 2:
The first gate layer acts as an intermediary between the substrate and the second gate layer. It provides a stable foundation with good interface states that prevents void formation, while still allowing the second gate layer to achieve precise threshold voltage control. The intermediary layer mediates between the conflicting requirements of thinness for precision and integrity for reliability.
3Device complexity
If a single gate layer is used to simplify the structure, then the device complexity is reduced, but the conductivity and resistance control are insufficient
Solution Approach 1:
The gate is segmented into functional layers: the first gate layer handles interface quality and blocking, while the second gate layer handles conductivity and resistance control. This segmentation enables precise control of electrical properties without requiring a single complex material, achieving better performance through functional division.
Solution Approach 2:
The multi-layer gate structure achieves multi-functionality where the combination of layers provides both blocking ability, interface quality, conductivity control, and resistance adjustment. This universal approach allows a single gate structure to perform multiple functions that would otherwise require separate components, effectively managing complexity while enhancing performance.
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
Improves the performance of semiconductor devices by effectively filling voids in the first gate layer and reducing resistance, thereby enhancing the electrical properties and interface states between layers.
Implementation Method 1
performing a thermal annealing process to cause atoms of the material of the second layer to pass through the first gate layer to fill the void
Data Source
AI summary
A semiconductor structure is provided. The semiconductor structure includes: a base substrate having an opening; and a first gate layer formed in the opening. In the first gate layer closes a top of the opening and the first gate layer includes at least one void. The semiconductor structure further includes a second gate layer formed on the first gate layer. An atomic radius of the material of the second gate layer is smaller than gaps among atoms of the material of the first gate layer and the void is filled by atoms of one of the material of the first gate layer and the material of the second gate layer.