Metal Phosphide ALD Using Phosphasilane for Uniform Thin Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for depositing metal phosphides, such as those used in semiconductor devices, face challenges with non-uniform thickness, particularly in high aspect ratio features, and involve hazardous materials like phosphine, leading to potential damage and unsuitability for highly scaled structures.
Innovation Solution
The use of phosphasilane precursors in atomic layer deposition (ALD) cycles, alternating with metal-containing precursors, enables the deposition of uniform metal phosphide layers less than 4 nanometers thick, overcoming the limitations of previous techniques by using safer and more controlled processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phosphine-based chemical vapor deposition is used to deposit metal phosphides, then deposition can be achieved, but the thickness is non-uniform particularly in high aspect ratio features and hazardous materials are involved
Solution Approach 1:
The patent changes the chemical parameters by replacing phosphine (PH3) with phosphine-free precursors such as phosphine hydrogen selenide (PH2SeH) or other alternative phosphorus-containing compounds. This substitution eliminates the hazardous material while maintaining the deposition capability and improving thickness uniformity through controlled precursor delivery and reaction conditions
Solution Approach 2:
The patent employs readily available phosphorus-containing precursors that can be delivered in controlled amounts and completely consumed in the deposition reaction, eliminating the need for handling and storing hazardous phosphine gas. The precursors are introduced as solids or liquids that vaporize and react completely, leaving no residual hazardous materials
2Manufacturing precision
If conventional deposition methods are used, then metal phosphide layers can be deposited, but precise thickness control for layers less than 4 nanometers is difficult
Solution Approach 1:
The patent employs atomic layer deposition (ALD) which uses periodic, self-limiting surface reactions. Each deposition cycle consists of alternating exposure to metal precursor and phosphorus precursor, where each precursor reacts completely with available surface sites before being purged. This periodic action enables precise control of film thickness at the nanometer and sub-nanometer scale by simply controlling the number of cycles
Solution Approach 2:
The ALD process inherently includes feedback control through self-limiting surface reactions. The reaction stops automatically when all surface sites are occupied, providing real-time feedback on completion without requiring external monitoring. This ensures uniform thickness even in high aspect ratio features where material transport might be limited
3Productivity
If phosphine plasma or extreme temperatures are used for metal phosphide deposition, then deposition can proceed, but adjacent features are damaged
Solution Approach 1:
The patent changes the thermal and chemical parameters by using phosphine-free precursors that decompose and react at lower, more controlled temperatures. This eliminates the need for phosphine plasma or extreme temperatures, preventing damage to adjacent sensitive features while maintaining productive deposition rates through optimized precursor delivery and reaction conditions
Solution Approach 2:
The patent uses alternative phosphorus-containing precursors as intermediaries that can transfer phosphorus to the metal surface without requiring harsh conditions. These precursors act as mediators that enable the deposition reaction to proceed at lower temperatures, protecting surrounding features from thermal and chemical damage
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 method allows for the deposition of uniform metal phosphide layers with precise thickness control, suitable for complex geometries, including high aspect ratio features, without the hazards associated with phosphine-based methods.
Implementation Method 1
applying a first pulse of a metal precursor to a substrate, purging the first pulse, applying a second pulse of a phosphasilane precursor, and purging the second pulse
Data Source
AI summary
Metal phosphide deposition via phosphoserine reactants and related structures are disclosed. An example method to deposit a metal phosphide layer via atomic layer deposition, the method including applying a first pulse of a metal precursor to a substrate, purging the first pulse, applying a second pulse of a phosphasilane precursor, and purging the second pulse.