Metal Ion Capture Layer Between Adjoining Fin Gates
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Solution Overview
Problem
As semiconductor devices scale down, metal gates with different work function metals (WFMs) adjoining each other lead to metal diffusion and migration, causing leakage current and reducing device performance.
Innovation Solution
The implementation of a metal ion capture layer, either in an interlayer dielectric layer or within the metal fill layer of adjoining metal gates, using a fluorine-rich oxide layer or by diffusing/implanting carbon, nitrogen, phosphorus, arsenic, antimony, and fluorine, which react with diffused metal ions to reduce migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal gates with different work function metals are used to adjoin each other in scaled-down semiconductor devices, then device storage capacity and processing speed are improved, but metal diffusion and migration occur causing leakage current and reduced device performance
Solution Approach 1:
A metal ion capture layer is introduced as an intermediary between adjoining metal gates with different work function metals. This capture layer, positioned at the interface region, selectively traps migrating metal ions and prevents them from causing leakage current, thereby resolving the contradiction between high-density device operation and device reliability
Solution Approach 2:
The metal ion capture layer is formed in advance during the fabrication process, before the metal gates are fully assembled and before metal ion migration can occur. This preliminary placement of the capture layer ensures that metal ions are trapped as they begin to migrate, preventing leakage current from developing
2Quantity of substance
If metal gates with different work function metals are used to adjoin each other, then device density is improved, but metal drifting and migration increase causing leakage current
Solution Approach 1:
The metal ion capture layer serves as a mediator between adjoining metal gates with different work function metals. Positioned at the interface, it selectively captures migrating metal ions through chemical affinity, preventing them from causing leakage current while allowing the high-density device structure to be maintained
Solution Approach 2:
The capture layer utilizes the natural tendency of metal ions to migrate towards regions with different work function metals and converts this harmful migration into a beneficial effect by directing the ions into the capture layer where they are trapped, thereby eliminating leakage current while maintaining device density
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 metal ion capture layer effectively reduces metal drifting and migration, decreases leakage current in metal gates with different WFMs, and enhances the overall performance of semiconductor devices.
Implementation Method 1
using a fluorine-rich oxide layer or by diffusing/implanting carbon, nitrogen, phosphorus, arsenic, antimony, and fluorine, which react with diffused metal ions to reduce migration
Implementation Method 2
forming a metal ion capture layer... which react with diffused metal ions to reduce migration
Implementation Method 3
by diffusing/implanting carbon, nitrogen, phosphorus, arsenic, antimony, and fluorine
Implementation Method 4
by diffusing/implanting carbon, nitrogen, phosphorus, arsenic, antimony, and fluorine
Data Source
AI summary
The present disclosure describes a semiconductor structure with a metal ion capture layer and a method for forming the structure. The method includes forming a first fin structure and a second fin structure on a substrate and forming a first gate structure over the first fin structure and a second gate structure over the second fin structure, where the first gate structure adjoins the second gate structure. The method further includes forming a dielectric layer on the first and second gate structures, removing a portion of the dielectric layer above an adjoining portion of the first and second gate structures to form an opening, and forming a metal ion capture layer in the opening.