Fin Structure Doping for Leakage Reduction
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Solution Overview
Problem
Microelectronic devices, such as non-planar transistor devices, face sub-fin leakage issues that increase device power consumption, and traditional methods to reduce this leakage often degrade electrical carrier mobility, affecting drive current and performance.
Innovation Solution
The method involves forming a free-standing fin structure on a substrate with a first portion without adjacent dielectric material and a second portion with dielectric material, where dopants are implanted to achieve a higher concentration in the sub-fin region, reducing sub-fin leakage while maintaining device mobility through specific implant and anneal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional doping methods are used to reduce sub-fin leakage, then sub-fin leakage is reduced, but electrical carrier mobility is degraded
Solution Approach 1:
The patent applies local quality by creating distinct dopant concentration zones within the fin structure. The sub-fin region receives a first dopant concentration while the main fin channel maintains a second, lower dopant concentration. This spatial differentiation allows the sub-fin region to have high doping for leakage suppression while the channel region preserves low doping for high carrier mobility, thus resolving the contradiction between reducing leakage and maintaining mobility.
2Object-generated harmful factors
If dopant concentration is increased in the sub-fin region, then sub-fin leakage is reduced, but device performance is degraded
Solution Approach 1:
The invention implements local quality by spatially separating the dopant concentration function into two distinct regions: the sub-fin region with high dopant concentration for leakage control, and the main fin channel with low dopant concentration for optimal drive current. This localized doping strategy ensures that high doping is applied only where necessary for leakage suppression, while the performance-critical channel region maintains low doping to preserve carrier mobility and drive current.
Solution Approach 2:
The fin structure is segmented into functionally distinct doping zones. The sub-fin region is separated from the main fin channel, each receiving tailored dopant concentrations appropriate to their specific functional requirements. This segmentation allows independent optimization of leakage control in the sub-fin region and drive current performance in the channel region.
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 effectively reduces sub-fin leakage and maintains high electrical carrier mobility, improving transistor operation by achieving an order of magnitude difference in dopant concentration between the fin and sub-fin regions.
Implementation Method 1
implanting the free standing fin with a dopant species
Implementation Method 2
specific implant and anneal processes
Data Source
AI summary
Methods and structures formed thereby are described relating to the doping non-planar fin structures. An embodiment of a structure includes a substrate, wherein the substrate comprises silicon, a fin on the substrate comprising a first portion and a second portion; and a dopant species, wherein the first portion comprises a first dopant species concentration, and the second portion comprises a second dopant species concentration, wherein the first dopant species concentration is substantially less than the second dopant species concentration.