Zinc Oxide Sputtering Target Composition Control
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Solution Overview
Problem
The composition difference between sputtering targets and films deposited using them can result in films with inadequate zinc content, affecting the crystallinity and crystal structure of oxide semiconductor films, particularly when using zinc oxide, leading to amorphous films due to insufficient elements for crystal formation.
Innovation Solution
A method for manufacturing sputtering targets involving the formation of crystals containing zinc oxide, crushing them, adding predetermined amounts of zinc oxide, and sintering to adjust the zinc proportion, ensuring the target has a higher zinc content than the desired film composition, which is then deposited using a sputtering method to achieve films with desired composition and high crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sputtering target with standard zinc oxide composition is used, then the deposition process is simple, but the deposited film has insufficient zinc content and poor crystallinity
Solution Approach 1:
The patent applies preliminary action by pre-forming crystal structures containing zinc oxide before crushing and sintering. This preliminary crystal formation ensures that the zinc oxide is properly incorporated into the target structure in advance, compensating for zinc loss during deposition and ensuring the final film has the correct composition and high crystallinity without requiring complex in-situ control during deposition
Solution Approach 2:
The patent changes the compositional parameters of the sputtering target by adding excess zinc oxide beyond the stoichiometric ratio. This parameter adjustment compensates for the zinc reduction that occurs during sputtering deposition, ensuring that the final film achieves the desired stoichiometric composition. The sintering temperature and duration are also optimized to achieve the right balance between zinc retention and crystal structure formation
2Stability of the object's composition
If zinc oxide proportion in the target is increased to compensate for deposition loss, then the film composition accuracy improves, but the target manufacturing complexity increases
Solution Approach 1:
The patent systematically adjusts the zinc oxide proportion parameter in the target composition to compensate for deposition losses. By establishing a specific excess zinc oxide ratio, the method stabilizes the final film composition while maintaining a relatively simple manufacturing process. The sintering parameters are optimized to achieve uniform distribution of zinc oxide without requiring complex multi-step fabrication procedures
3Reliability
If the target composition is adjusted to ensure high zinc content, then the film crystallinity improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent uses preliminary crystal formation before crushing and sintering to ensure proper zinc oxide incorporation. This preliminary structuring action guarantees that the zinc oxide is already in the correct crystalline form and distribution before the target is finalized, ensuring high film crystallinity while maintaining manageable composition control during manufacturing
Solution Approach 2:
The patent optimizes sintering temperature and duration parameters to achieve the right balance between zinc retention and crystal structure development. By carefully controlling these thermal parameters, the method ensures high film crystallinity and proper composition without requiring extremely tight tolerances during the mixing and fabrication stages
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 deposition of films with compositions matching or nearing stoichiometric compositions, ensuring high crystallinity and desired properties, particularly for oxide semiconductor films used in semiconductor devices.
Implementation Method 1
an oxide semiconductor layer is formed by a sputtering method or the like
Implementation Method 2
performing sintering
Data Source
AI summary
When an oxide semiconductor is deposited by a sputtering method, there is a difference in composition between a sputtering target and a film deposited using the sputtering target in some cases depending on a material of the oxide semiconductor. In manufacturing a sputtering target containing zinc oxide, a crystal which contains zinc oxide is formed in advance, the crystal is crushed, and then a predetermined amount of zinc oxide is added and mixed. After that, the resulting object is sintered to form the sputtering target. The composition of the sputtering target is adjusted by setting the proportion of zinc in the sputtering target higher than that of zinc in a film having a desired composition which is obtained at last, in consideration of the amount of zinc which is reduced at the time of deposition by a sputtering method, the amount of zinc which is reduced at the time of sintering, and the like.