Cyclic Tin Amide Precursors for Low-Temperature ALD
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current atomic layer deposition (ALD) processes for tin and lead compounds require high temperatures, which are unsuitable for thermally sensitive substrates like plastics and organic light emitting diodes, and often result in films with defects such as pin-holes and chloride contamination.
Innovation Solution
The use of volatile tin or lead cyclic amides as precursors in ALD processes, reacted with gases like hydrogen sulfide or oxygen-containing compounds, allows for the deposition of uniform, conformal, and pin-hole-free films at lower temperatures, avoiding plasma damage and achieving good adhesion to substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ALD processes use high temperature deposition for tin and lead compounds, then film density and crystallinity are improved, but substrate thermal damage occurs and film defects such as pin-holes and chloride contamination increase
Solution Approach 1:
The patent changes the chemical parameters of the precursor molecules by introducing cyclic amide structures with specific substituents (R1-R6 groups). This chemical parameter change enables the precursors to decompose at lower temperatures (below 200°C), allowing high-quality film deposition without substrate thermal damage. The cyclic amide structure provides controlled decomposition that eliminates the need for high-temperature processing while maintaining film density and crystallinity.
2Manufacturing precision
If conventional ALD processes use high temperature deposition, then film density is improved, but film defects such as pin-holes and chloride contamination increase
Solution Approach 1:
The patent extracts and removes harmful elements (chloride, oxygen) from the deposition process by using carefully selected cyclic amide precursors that decompose cleanly. The precursor molecules are designed to release only the desired metal atoms without leaving harmful residues. This extraction of harmful factors from the chemical reaction process eliminates pin-hole defects and chloride contamination while maintaining high film density.
Solution Approach 2:
The cyclic amide structure acts as an intermediary that controls the decomposition process. It serves as a mediator between the metal source and the substrate, ensuring clean decomposition at low temperatures. The amide linkage facilitates controlled release of metal atoms without direct contact between harmful substances and the substrate, preventing both thermal damage and film defects.
3Temperature
If plasma-enhanced ALD is used to deposit at lower temperatures, then substrate thermal damage is reduced, but device complexity increases and uniform film production in high aspect ratio structures is difficult
Solution Approach 1:
The patent replaces the plasma-enhanced mechanical/physical system with a purely chemical solution. Instead of using plasma generation equipment to activate reactions at low temperatures, the invention uses chemically active cyclic amide precursors that spontaneously decompose at low temperatures. This substitution eliminates complex plasma generating systems while achieving the same low-temperature deposition goal through chemical means alone.
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 enables the production of films with high electrical conductivity, smooth surfaces, and good step coverage on various substrates, including those with complex structures, while maintaining film quality and reducing contamination and temperature requirements.
Implementation Method 1
Vapors of a volatile tin cyclic amide compound are reacted with hydrogen sulfide gas at a surface to produce thin layers of tin sulfide on the surface
Implementation Method 2
Another aspect of the present disclosure includes the use of oxygen or other oxygen containing compounds to oxidize the deposited tin or lead film
Implementation Method 3
This present disclosure relates to materials and processes for deposition of films containing metals on solid substrates
Data Source
AI summary
Novel cyclic amides containing tin or lead are disclosed. These cyclic amides can be used for atomic layer deposition or chemical vapor deposition of tin or lead as well as their oxides, sulfides, selenides, nitrides, phosphides, carbides, silicides or borides or other compounds. Tin(IV) oxide, SnO2, films were deposited by reaction of a cyclic tin amide vapor and H2O2 or NO2 as oxygen sources. The films have high purity, smoothness, transparency, electrical conductivity, density, and uniform thickness even inside very narrow holes or trenches. Deposition temperatures are low enough for thermally sensitive substrates such as plastics. Suitable applications of these films include displays, light-emitting diodes, solar cells and gas sensors. Doping SnO2 with aluminum was used to reduce its conductivity, making material suitable as the active semiconductor layer in electron multipliers or transparent transistors. Deposition using the same tin precursor and H2S deposited tin monosulfide, SnS, a material suitable for solar cells.