Self-Limited Inner Spacer for Gate-All-Around Nanosheet FET
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Solution Overview
Problem
As semiconductor integrated circuits scale down, forming inner spacers for gate-all-around nanosheet field effect transistors becomes increasingly difficult without pinch-off of the gate spacer, affecting source/drain isolation.
Innovation Solution
A semiconductor structure with a self-limited inner spacer composed of rare earth doped germanium dioxide is used, providing source/drain isolation between rare earth metal silicide ohmic contacts, and a method involving the formation of rare earth metal doped germanium dioxide layers and subsequent annealing to create both ohmic contacts and spacers is employed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional inner spacer formation methods are used in scaled-down devices, then source/drain isolation can be achieved, but gate spacer pinch-off occurs making the process increasingly difficult
Solution Approach 1:
The rare earth metal doped germanium dioxide layer automatically forms the inner spacer with precise dimensions through self-limited growth, eliminating the need for complex external control mechanisms. The material inherently stops growing at the correct thickness, providing self-regulated spacer formation that prevents pinch-off while maintaining manufacturing precision in scaled-down devices
Solution Approach 2:
The invention changes the material parameters by using rare earth metal doped germanium dioxide instead of conventional spacer materials. This material parameter change enables self-limited growth behavior and prevents gate spacer pinch-off, resolving the manufacturing difficulty while maintaining precision in nanoscale devices
2Productivity
If device scaling continues to improve performance, then drive current increases within given layout, but inner spacer formation becomes increasingly difficult without pinch-off
Solution Approach 1:
The self-limited growth mechanism of rare earth metal doped germanium dioxide provides automatic precision control at nanoscale dimensions, enabling inner spacer formation to maintain manufacturing precision even as device scaling progresses and dimensions continue to shrink
Solution Approach 2:
The use of composite rare earth metal doped germanium dioxide combines the benefits of germanium dioxide's self-limited growth property with rare earth metal doping that enhances material stability and prevents pinch-off, maintaining manufacturing precision across scaling generations
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 device performance by effectively isolating source/drain regions and preventing gate spacer pinch-off, enhancing the scalability and efficiency of nanosheet transistor structures.
Implementation Method 1
An anneal is then performed to convert the rare earth metal doped germanium dioxide layer that is in physical contact with each source/drain (S/D) extension region into a rare earth metal silicide ohmic contact
Data Source
AI summary
A semiconductor structure containing a gate-all-around nanosheet field effect transistor having a self-limited inner spacer composed of a rare earth doped germanium dioxide that provides source/drain isolation between rare earth metal silicide ohmic contacts is provided.