Selective Epitaxy Inhibitor for Low-Temperature Silicon Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current selective epitaxy processes require high temperatures and struggle to maintain selectivity at lower temperatures, leading to uncontrolled growth and nitridation, and result in low growth rates and amorphous silicon or germanium nucleation on dielectric surfaces.
Innovation Solution
A method involving precleaning and applying an inhibitor species to dielectric surfaces to prevent nucleation, followed by epitaxial deposition at temperatures below 600°C using a precursor and etchant, with chlorine as the etchant to reduce overall process temperature and increase growth rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high reaction temperature (above 800°C) is used to maintain selectivity during epitaxial growth, then selectivity is improved, but thermal budget is increased and uncontrolled nitridation reactions occur
Solution Approach 1:
The dielectric surface is treated with a silane-based inhibitor species before the epitaxial growth process begins. This preliminary action creates a protective layer that prevents silicon precursor decomposition and amorphous silicon formation on dielectric surfaces, enabling selective epitaxy at lower temperatures without compromising selectivity
Solution Approach 2:
A silane-based inhibitor species acts as an intermediary between the silicon precursor and the dielectric surface. This intermediary prevents direct interaction that would lead to unwanted amorphous silicon nucleation, allowing the epitaxial process to proceed selectively at reduced temperatures
2Temperature
If low reaction temperature (below 600°C) is used to reduce thermal budget, then thermal budget is reduced, but selectivity is lost and amorphous silicon or germanium nucleation occurs on dielectric surfaces
Solution Approach 1:
The dielectric surface is pre-treated with a silane-based inhibitor that forms a protective barrier before low-temperature epitaxial growth. This preliminary protection enables the process to maintain selectivity even at temperatures below 600°C where HCl dissociation efficiency is poor
Solution Approach 2:
The process changes the chemical state of the dielectric surface by applying a silane-based inhibitor layer, which fundamentally alters the surface properties to prevent unwanted nucleation. This parameter change enables low-temperature processing while maintaining selectivity
3Reliability
If insufficient silicon precursor is administered to maintain selectivity, then selectivity is improved, but the etching reaction dominates and overall process speed is reduced
Solution Approach 1:
The silane-based inhibitor species serves as an intermediary that protects the dielectric surface from silicon precursor decomposition. This protection allows higher silicon precursor concentrations to be used without causing amorphous silicon formation, thereby increasing deposition rate while maintaining selectivity
Solution Approach 2:
By pre-applying the inhibitor layer, the system can tolerate higher silicon precursor flux during epitaxial growth without compromising selectivity. This enables faster deposition rates while maintaining the desired selective growth characteristics
4Manufacturing precision
If insufficient etchant precursor is administered to avoid over-etching, then substrate feature integrity is improved, but deposition reaction dominates and selectivity is reduced
Solution Approach 1:
The silane-based inhibitor acts as a mediator that prevents direct silicon precursor-dielectric interactions. This mediation allows the etching process to be more aggressive without causing damage to dielectric surfaces, as the inhibitor protects against unwanted reactions while permitting controlled etching where needed
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
Achieves selective epitaxial deposition of silicon- or germanium-containing materials at low temperatures with improved selectivity and growth rates, minimizing amorphous growth on dielectric surfaces and reducing thermal budget considerations.
Implementation Method 1
applying an inhibitor species to the dielectric surfaces
Implementation Method 2
exposing the substrate to a precursor
Implementation Method 3
with chlorine as the etchant to reduce overall process temperature and increase growth rate
Data Source
AI summary
A method of forming a film on a substrate having silicon surfaces and dielectric surfaces includes precleaning the substrate; applying an inhibitor species to the dielectric surfaces; and exposing the substrate to a precursor while maintaining a temperature of less than about 600 degrees Celsius.