ALD Thin Film Deposition Using Deposition-Enhancing Agents
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Solution Overview
Problem
Atomic layer deposition (ALD) processes face challenges in producing metal-containing films at low temperatures with low halogen impurity levels, as high temperatures required for low impurity content can lead to decomposition of precursors and loss of conformality and uniformity, and existing methods result in high chlorine content or amorphous films with reduced growth rates.
Innovation Solution
Incorporating a deposition-enhancing agent such as hydrocarbons, hydrogen, or boron compounds in the ALD process to reduce impurity levels and enable film growth at lower temperatures, specifically using alternating pulses of metal source chemicals, carbon or silicon source chemicals, and deposition-enhancing agents like acetylene or triethyl boron to form metal carbides, oxides, or silicides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high deposition temperature is used to reduce halogen impurity levels, then impurity content is reduced, but precursor decomposition occurs and conformality and uniformity are lost
Solution Approach 1:
A deposition-enhancing agent (hydrocarbon, hydrogen, or boron compound) is introduced as an intermediary substance that facilitates halogen removal from the film at lower temperatures. The agent reacts with adsorbed halogen species on the substrate surface, enabling impurity reduction without requiring high temperatures that would cause precursor decomposition and loss of conformality.
Solution Approach 2:
The process changes the temperature parameter from high to low range, and introduces a chemical agent parameter to compensate for the reduced thermal energy. This parameter change allows the system to achieve halogen removal through chemical reaction with the deposition-enhancing agent rather than thermal decomposition.
2Reliability
If low deposition temperature is used to maintain conformality and uniformity, then conformality is maintained, but halogen impurity levels increase
Solution Approach 1:
The deposition-enhancing agent serves as a chemical intermediary that enables halogen removal at low temperatures. By introducing this agent, the system can achieve effective halogen elimination through surface reactions without compromising the conformal deposition that results from low-temperature processing.
Solution Approach 2:
The process replaces the mechanical/thermal mechanism (high temperature thermal decomposition) with a chemical mechanism (reaction with deposition-enhancing agent). This substitution allows halogen removal to occur through chemical reaction rather than thermal energy input, preserving conformality.
3Manufacturing precision
If high growth temperature is chosen to reduce impurity content, then impurity levels are reduced, but growth rate is substantially lowered due to reduced reactive active sites
Solution Approach 1:
The process changes the temperature parameter to low range to maintain high density of reactive active sites, which sustains high growth rate. Simultaneously, a chemical agent parameter (deposition-enhancing agent) is introduced to enable impurity removal, thus achieving both high productivity and low impurity content through parameter optimization.
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 thin films with reduced impurity levels and improved growth rates, maintaining conformality and uniformity, even at lower temperatures, effectively addressing the limitations of existing ALD methods.
Implementation Method 1
a deposition-enhancing agent is capable of removing halides from the substrate surface and/or from the reaction space
Implementation Method 2
exposing the substrate to a first precursor, removing unreacted first reactant and reaction byproducts from the reaction chamber
Implementation Method 3
The deposition conditions and precursors are selected to ensure self-saturating reactions, such that an adsorbed layer in one pulse leaves a surface termination that is non-reactive with the gas phase reactants of the same pulse
Data Source
AI summary
Methods of producing metal-containing thin films with low impurity contents on a substrate by atomic layer deposition (ALD) are provided. The methods preferably comprise contacting a substrate with alternating and sequential pulses of a metal source chemical, a second source chemical and a deposition enhancing agent. The deposition enhancing agent is preferably selected from the group consisting of hydrocarbons, hydrogen, hydrogen plasma, hydrogen radicals, silanes, germanium compounds, nitrogen compounds, and boron compounds. In some embodiments, the deposition-enhancing agent reacts with halide contaminants in the growing thin film, improving film properties.