Multiphase Molybdenum Oxide Target for Stable MoOx Sputtering
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Solution Overview
Problem
Existing molybdenum oxide target materials for PVD coating systems face challenges in achieving high-quality, uniformly thick layers with precise stoichiometric composition and conductivity, requiring complex and costly process technology, and are prone to hysteresis effects and particle formation due to limited oxygen content adjustability and density.
Innovation Solution
A multiphase molybdenum oxide target material with a homogeneous structure comprising MoO₂ and substoichiometric MoO₃-y phases, allowing for a wide range of oxygen content adjustment and high electrical conductivity, minimizing the need for additional oxygen during sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reactive sputtering is used with metallic molybdenum target to produce substoichiometric MoOx layers, then the desired oxygen content and electro-optical properties are achieved, but the process becomes complex, expensive, and unstable with hysteresis effects
Solution Approach 1:
The target material is pre-prepared with a specific substoichiometric composition (MoO2.5 to MoO2.98) before the sputtering process. This preliminary preparation of the target with controlled oxygen content eliminates the need for complex reactive sputtering processes to adjust oxygen content during deposition, thereby simplifying the process while maintaining precise stoichiometric control
Solution Approach 2:
The invention changes the fundamental parameter of the target material from metallic molybdenum to substoichiometric molybdenum oxide. This parameter change allows direct deposition of substoichiometric MoOx layers without requiring reactive sputtering with oxygen gas, thus eliminating hysteresis effects and process complexity while maintaining manufacturing precision
2Stability of the object's composition
If reactive sputtering is used to deposit MoOx layers with precise oxygen content, then homogeneous layer properties are achieved, but process stability deteriorates due to hysteresis effects when oxygen partial pressure changes
Solution Approach 1:
The invention extracts the oxygen supply step from the sputtering process by incorporating the desired oxygen content directly into the target material. This eliminates the need for reactive sputtering with oxygen gas, thereby removing the source of hysteresis effects and process instability while still achieving homogeneous layer properties through the pre-configured target composition
3Quantity of substance
If oxide-ceramic target materials like MoO2 are used, then the target contains sufficient oxygen for sputtering, but the relative density is too low leading to lightning discharges and particle formation
Solution Approach 1:
The invention uses composite target materials consisting of substoichiometric molybdenum oxide phases (MoO3-y where y=0.05 to 0.25) combined with appropriate binders or other molybdenum oxide phases. This composite structure achieves both sufficient oxygen content for direct sputtering and high relative density (>95%) to prevent arcs and particle formation, resolving the contradiction between oxygen content and process stability
4Quantity of substance
If substoichiometric MoOx target materials with low relative density are used, then oxygen content is sufficient, but particle formation occurs during coating due to lightning discharges
Solution Approach 1:
The invention develops composite target materials that combine substoichiometric molybdenum oxide phases with binders or structural phases to achieve high relative density (>95%). This composite structure eliminates porosity that would cause lightning discharges and particle formation, while maintaining sufficient oxygen content for direct sputtering, thus eliminating harmful particle formation
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
Enables high-quality, uniformly thick layers with improved process stability and reduced particle formation, achieving high density and precise oxygen content without complex reactive sputtering, thus enhancing deposition efficiency and reducing costs.
Implementation Method 1
Target materials made of molybdenum oxide (MoOx) are used in cathode sputtering systems such as PVD coating systems (PVD English physical vapor deposition) in order to deposit layers containing molybdenum oxide from the gas phase in a vacuum process. In this coating process (sputtering process) the layer-forming particles are transferred from the (sputter) target into the gas phase
Data Source
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AI summary
The invention relates to an electrically conductive, oxide target material comprising a substoichiometric molybdenum oxide phase fraction of at least 60 vol.%, a MoO2 phase with a fraction of 2-20 vol.%, and optionally a MoO3 phase with a fraction of 0-20 vol.%. The substoichiometric molybdenum oxide phase fraction is formed by one or more substoichiometric MoO3 y-phase(s), where y is in the range of 0.05 to 0.25.