FinFET Uniform Doping via Alternating Ligand Cycles
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Solution Overview
Problem
The challenge in manufacturing FinFET structures lies in uniformly doping the impurity on the upper surface and side surfaces of the fin structure in silicon substrates, as typical crystalline silicon is insulating and dopants tend to move straight, making uniform doping difficult.
Innovation Solution
A method involving the formation of dopant-containing films using alternating gases with different ligands, such as BCl3 and B2H6, followed by annealing to diffuse the dopant into the silicon film, ensuring uniform doping of the silicon substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dopant-containing gas is supplied to dope the fin structure, then the silicon film becomes conductive, but the dopant ions move straight and fail to uniformly dope the surface of the fin structure
Solution Approach 1:
The doping process is divided into multiple cycles, each consisting of two steps: first supplying a dopant-containing gas with a first ligand to form a dopant-containing film, then supplying a dopant-containing gas with a second ligand different from and reactive with the first ligand to form another dopant-containing film. This segmentation allows the dopant to be deposited in controlled layers that conform to the fin structure geometry, achieving uniform doping on both upper surfaces and side surfaces.
Solution Approach 2:
The patent employs periodic alternation between different dopant-containing gases with different ligands. Each cycle alternates between the first ligand-based gas and the second ligand-based gas, creating a periodic deposition pattern that ensures uniform dopant distribution across the fin structure surfaces through repeated conformal coating cycles.
2Strength
If typical crystalline silicon is used, then the substrate has good structural properties, but the silicon is insulating and requires doping to become conductive
Solution Approach 1:
The patent changes the electrical parameter of the silicon substrate by introducing dopant atoms through the multi-cycle gas supply process. The dopant concentration is precisely controlled by adjusting the number of cycles and the supply conditions of the dopant-containing gases, transforming the insulating crystalline silicon into a conductive doped silicon film while preserving the underlying crystal structure.
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 allows for the formation of boron films with low impurity concentrations and superior step coverage, selectively doping the silicon film while minimizing impurity presence on the silicon oxide film, resulting in a uniformly doped silicon film with enhanced performance.
Implementation Method 1
forming a first dopant-containing film by supplying a first dopant-containing gas containing the dopant and a first ligand to a substrate having thereon the silicon film
Implementation Method 2
forming a doped silicon film by annealing the substrate having the dopant-containing film thereon to diffuse the dopant into the silicon film
Implementation Method 3
forming a doped silicon film by annealing the substrate having the dopant-containing film thereon to diffuse the dopant into the silicon film
Data Source
AI summary
Described is a technique for uniformly doping a silicon substrate having a Fin structure with a dopant. A method of manufacturing a semiconductor device may includes: (a) forming a dopant-containing film containing a dopant on a silicon film by performing a cycle a predetermined number of times, the cycle including: (a-1) forming a first dopant-containing film by supplying a first dopant-containing gas containing the dopant and a first ligand to a substrate having thereon the silicon film and one of a silicon oxide film and a silicon nitride film; and (a-2) forming a second dopant-containing film by supplying a second dopant-containing gas containing the dopant and a second ligand different from and reactive with the first ligand to the substrate; and (b) forming a doped silicon film by annealing the substrate having the dopant-containing film thereon to diffuse the dopant into the silicon film.