GAA Nanowire Semiconductor Structure with Variable Epitaxy Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gate-all-around (GAA) structures in semiconductor devices suffer from nanowire thickness variations due to unequal thermal exposure during epitaxy stack formation, leading to inconsistent gate control and loading effects in metal gate filling.
Innovation Solution
A new epitaxy stack design with alternating layers of nanowire materials, where the thicknesses of each layer are systematically varied to ensure uniformity and reduce thickness differences between nanowires, thereby improving gate control and reducing loading effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional gate-all-around structures are used with equal thickness alternating layers, then the structure is simple to manufacture, but nanowire thickness variations occur due to unequal thermal exposure leading to inconsistent gate control
Solution Approach 1:
The patent applies local quality by varying the thickness of alternating nanowire material layers at different positions within the epitaxy stack. Specifically, the first nanowire material layer has a first thickness and the second nanowire material layer has a second thickness that is different from the first thickness. This local variation in layer thickness compensates for unequal thermal exposure during formation, ensuring uniform nanowire thickness throughout the stack and improving gate control consistency.
2Manufacturing precision
If alternating layers of different thicknesses are used to compensate for thermal exposure, then nanowire thickness uniformity is improved, but the epitaxy stack design becomes more complex
Solution Approach 1:
The patent applies parameter changes by systematically varying the thickness parameters of alternating nanowire material layers in the epitaxy stack. The first nanowire material layer is formed with a first thickness and the second nanowire material layer is formed with a second thickness that differs from the first thickness. This parameter variation is designed to compensate for unequal thermal exposure during formation, achieving uniform nanowire thickness while maintaining manufacturability through controlled parameter adjustments.
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 new structure achieves greater dimensional uniformity of Si and SiGe nanowires, enhancing gate control and alleviating metal gate filling issues, thus improving device yield and performance.
Implementation Method 1
epitaxy stack formation includes forming an alternating first nanowire material layer and second nanowire material layer
Data Source
AI summary
A semiconductor structure is provided. The semiconductor structure includes a first nanowire over a semiconductor fin. The semiconductor structure also includes a second nanowire over the first nanowire and a third nanowire over the second nanowire. The semiconductor structure further includes a source/drain wrapping around the first nanowire, the second nanowire and the third nanowire. A thickness of a first portion of the source/drain vertically sandwiched between the first nanowire and the second nanowire is different from a thickness of a second portion of the source/drain vertically sandwiched between the second nanowire and the third nanowire.