SiGe Fin Diffusion via Cladding Oxidation for FinFET Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming SiGe fins in finFET semiconductor devices result in non-uniformity and defects due to epitaxial growth from a Si seed layer, limiting germanium concentration and carrier mobility improvements.
Innovation Solution
A method involving the epitaxial growth of a silicon germanium cladding layer on semiconductor fins, followed by oxidation to diffuse ions into the fins, converting the cladding layer to an oxide and removing it to expose a diffused fin portion with enhanced electron hole mobility, thereby integrating a high Ge concentration within the fin structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If SiGe fins are formed by epitaxially growing from a Si seed layer, then the threshold voltage is reduced and drive current is increased, but the fin growth becomes non-uniform and defects occur during the growth process
Solution Approach 1:
A SiGe cladding layer is introduced as an intermediary material that is epitaxially grown on the Si fin, then oxidized to form a SiGe diffused portion. This mediator approach avoids direct epitaxial growth from Si seed layer while still achieving SiGe fin formation, eliminating the non-uniformity and defects associated with conventional epitaxial growth methods
Solution Approach 2:
The method changes the formation parameters by using oxidation of a SiGe cladding layer instead of direct epitaxial growth. This parameter change (from direct growth to oxidation-based formation) enables uniform fin structures while achieving the desired SiGe composition for improved carrier mobility and drive current
2Quantity of substance
If conventional methods are used to form SiGe fins, then the germanium concentration is limited, but the carrier mobility improvement is insufficient
Solution Approach 1:
The SiGe cladding layer is preliminarily formed on the Si fin before the actual SiGe fin formation through oxidation. This preliminary action allows for controlled introduction of Ge atoms into the fin structure, achieving high germanium concentration without the limitations of conventional direct epitaxial growth methods
Solution Approach 2:
The mechanical epitaxial growth process is replaced with a chemical oxidation process. Instead of mechanically growing SiGe from a seed layer, the method uses chemical oxidation of a SiGe cladding layer to form the SiGe fin, enabling higher Ge concentration and improved carrier mobility
3Quantity of substance
If a cladding layer is epitaxially grown and then oxidized to form SiGe fin, then high Ge concentration is achieved, but additional process steps are required
Solution Approach 1:
The formation of the SiGe fin is merged with the gate formation process by using the same oxidation step that forms the SiGe diffused portion in the fin. This combining of operations reduces the total number of process steps while achieving high Ge concentration in the fin 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 improves electron hole mobility by integrating a high Ge concentration within the SiGe fin, reducing defects and non-uniformity, and enhancing the performance of finFET devices.
Implementation Method 1
ions are condensed therefrom and are diffused into the at least one semiconductor fin
Implementation Method 2
The cladding layer is oxidized such that r such that ions are condensed therefrom
Data Source
AI summary
A method of fabricating a semiconductor device includes forming at least one semiconductor fin on a semiconductor substrate. A cladding layer is epitaxially grown on a portion of the at least one semiconductor fin. The cladding layer is oxidized such that r such that ions are condensed therefrom and are diffused into the at least one semiconductor fin while the cladding layer is converted to an oxide layer. The oxide layer is removed to expose the at least one semiconductor fin having a diffused fin portion that enhances electron hole mobility therethrough.