Silicon Target Conductive Layer for Sputtering Dust Reduction
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Solution Overview
Problem
The generation of dust during sputtering film formation using n-type silicon targets leads to defects in the formed silicon-containing thin films, as charge-up occurs at the bonding interface between the target material and the backing plate, resulting in poor film quality.
Innovation Solution
A silicon target for sputtering with a conductive layer made of a material having a smaller work function than the n-type silicon target material is attached to a metallic backing plate via a bonding layer, preventing electric energy barriers and reducing charge-up, thereby inhibiting dust generation. The conductive layer is preferably made of a lanthanoid, rare-earth, alkali metal, or alkali-earth element, and the silicon target material is single crystal with a volume resistivity of 1 Ωcm or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conductive layer with smaller work function is added to the silicon target material, then dust generation is reduced and film quality is improved, but the device structure becomes more complex
Solution Approach 1:
The target is divided into functionally distinct layers: the silicon target material layer and the conductive layer with smaller work function. This segmentation allows each layer to perform its specific function - the silicon layer provides the sputtering material while the conductive layer prevents charge-up and dust generation, thereby resolving the contradiction between film quality and structural complexity.
Solution Approach 2:
The invention uses a composite structure combining silicon target material with a conductive layer made of materials having smaller work function (such as aluminum, magnesium, or their alloys). This composite material approach enables the target to simultaneously achieve good electrical conductivity for dust prevention and appropriate sputtering characteristics, thus improving film quality without excessive complexity.
2Object-generated harmful factors
If the work function of the conductive layer is reduced to prevent charge-up, then dust generation is inhibited, but the selection of suitable materials becomes more restricted
Solution Approach 1:
The invention changes the key parameter of work function by selecting conductive layer materials with smaller work function values than the silicon target material (such as aluminum with 4.28 eV or magnesium with 3.66 eV). This parameter change effectively reduces charge-up and dust generation while maintaining a reasonable range of material choices within the alkaline earth metal and aluminum family, thus resolving the contradiction between dust prevention and material selection flexibility.
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 significantly reduces dust generation during sputtering, enabling the formation of high-quality silicon-containing thin films by ensuring charge-up is minimized, thus improving film quality and reducing defects.
Implementation Method 1
a conductive layer made of a material having a smaller work function than that of the silicon target material is provided on a surface of the silicon target material on the bonding material side
Implementation Method 2
Silicon-containing thin films such as a silicon film, a silicon oxide film, a silicon nitride film, and a silicon nitride-oxide film are used in various fields. A sputtering method using a silicon-containing target material has been widely used to form the silicon-containing thin films
Data Source
AI summary
A silicon target for sputtering film formation which enables formation of a high-quality silicon-containing thin film by inhibiting dust generation during sputtering film formation is provided. An n-type silicon target material 10 and a metallic backing plate 20 are attached to each other via a bonding layer 40. A conductive layer 30 made of a material having a smaller work function than that of the silicon target material 10 is provided on a surface of the silicon target material 10 on the bonding layer 40 side. That is, the silicon target material 10 is attached to the metallic backing plate 20 via the conductive layer 30 and the bonding layer 40. In a case of single-crystal silicon, a work function of n-type silicon is generally 4.05 eV. A work function of a material of the conductive layer 30 needs to be smaller than 4.05 eV.