LaB6 Sintered Body Nitrogen Dispersion Purity
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Solution Overview
Problem
Conventional LaB6 sintered bodies produced using commercially available powders contain impurities that increase the work function of LaB6 films, leading to poor crystallinity and adhesion issues due to differences in thermal expansion and lattice constants with substrates, and have low relative density with pores that contaminate vacuum chambers during sputtering.
Innovation Solution
A method involving the sintering of high-purity LaB6 powder with nitrogen dispersion to create a sintered body with nitrogen content between 0.1-3 mass% and impurities less than 0.3 volume%, achieving a relative density of 88% or more, which reduces internal stress and maintains low work function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If commercially available LaB6 powder is used for sintering, then the production process is simple and fast, but the sintered body contains impurities (oxides, carbides, complex oxides) that increase work function and reduce film quality
Solution Approach 1:
The patent applies preliminary action by performing acid treatment and oxidation processes on the LaB6 powder before sintering to remove impurities. The powder is heated in an oxidizing atmosphere to convert carbides and complex oxides into removable forms, then treated with acids to dissolve oxides, ensuring high purity before the sintering step.
Solution Approach 2:
The patent changes physical and chemical parameters of the powder through controlled heating in oxidizing atmospheres at specific temperatures, followed by acid treatment with controlled concentration and time, to transform impurity forms and achieve the required purity level while maintaining productivity.
2Manufacturing precision
If high-purity LaB6 powder is used, then the work function and crystallinity are improved, but the sintering process becomes more complex and time-consuming
Solution Approach 1:
The patent merges multiple treatment steps (oxidation, acid treatment, drying) into a integrated preliminary processing sequence that can be performed in a standardized workflow. The acid treatment and oxidation are combined in a systematic approach that, while adding steps, creates a reproducible and manageable process for achieving high purity.
Solution Approach 2:
The patent optimizes process parameters such as heating temperature, oxidation time, acid concentration, and treatment duration to achieve the desired purity level. By carefully controlling these parameters, the process becomes more efficient and less complex, as precise control reduces the need for repeated treatments and troubleshooting.
3Productivity
If conventional sintering is used, then the production is efficient, but the relative density is low (pores remain) causing vacuum chamber contamination during sputtering
Solution Approach 1:
The patent applies preliminary action by thoroughly removing impurities and optimizing powder characteristics before sintering. The acid treatment and oxidation processes ensure that the powder is in the optimal state for sintering, which facilitates densification and reduces pore formation during the sintering process itself.
Solution Approach 2:
The patent optimizes sintering parameters including temperature, time, and atmosphere based on the pre-treated powder characteristics. The controlled oxidation and acid treatment prior to sintering create a powder structure that responds better to sintering, achieving higher density while maintaining production efficiency through optimized parameter selection.
4Ease of manufacture
If impurities are present in the target, then the target can be produced from conventional powder, but the impurities are incorporated in the sputtering film increasing work function and reducing adhesion
Solution Approach 1:
The patent applies preliminary action by removing impurities from the powder through oxidation and acid treatment before sintering. This preliminary purification ensures that the resulting sintered body and subsequent sputtering film have minimal impurity content, achieving high film quality while maintaining ease of production through a standardized preliminary treatment process.
Solution Approach 2:
The patent applies the extraction principle by removing harmful impurities (oxides, carbides, complex oxides) from the LaB6 powder through acid treatment and oxidation processes. This extraction of unwanted components before sintering ensures that the final film produced from the target has high purity and excellent quality.
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
The approach results in LaB6 films with high purity, excellent crystallinity, and low work function, improving adhesion and reducing contamination from pores, making them suitable for high-performance applications.
Implementation Method 1
a method of producing the sintered body comprising: heating the lanthanum hexaboride powder at a temperature of 600°C. or more and 800°C. or less in an oxidizing atmosphere; acid-treating the heated lanthanum hexaboride powder; sintering the acid-treated lanthanum hexaboride powder at a temperature of 1800°C. or more and a pressure of 30 MPa or more under a nitrogen gas atmosphere
Implementation Method 2
heating the lanthanum hexaboride powder at a temperature of 600°C. or more and 800°C. or less in an oxidizing atmosphere
Data Source
AI summary
Disclosed are: a lanthanum hexaboride sintered body which contains lanthanum hexaboride as the main component, has an element nitrogen content of 0.1 to 3 mass % inclusive, contains an impurity composed of element carbon and/or at least two elements selected from La, C, O and B at a content of 0.3 vol % or less, and has a relative density of 88% or more; and a target comprising the lanthanum hexaboride sintered body. An LaB6 sintered body can be provided, which enables the production of a highly pure and dense LaB6 thin film having excellent crystallinity and a good work function and which is suitable for a sputtering target or the like.