High-Purity Silicon Target

Core Features

1. Extreme Purity and Ultra-Low Impurity Control

   Adopting float zone (FZ) or Czochralski (CZ) method combined with chemical purification, monocrystalline silicon targets have a total metallic impurity (Fe, Cu, Ni, Na, K, etc.) content ≤1 ppb, carbon impurity ≤2 ppb and oxygen impurity ≤5 ppb; polycrystalline silicon targets have a total metallic impurity content ≤5 ppb with no harmful impurity precipitation. Ultra-pure doping customization is supported, with boron (B) or phosphorus (P) doping concentration precisely controllable (10¹⁵-10¹⁹ atoms/cm³) and doping uniformity deviation ≤±3%, meeting the preparation requirements of conductive high-purity silicon films.
2. Ultra-High Density and Excellent Sputtering Stability

   Treated by hot isostatic pressing (HIP) or spark plasma sintering (SPS) processes, the target density reaches ≥99.9% with porosity ≤0.1%, almost eliminating particle contamination and arcing during sputtering. Monocrystalline silicon targets have intact lattice and controllable crystal orientation (e.g., <100>, <111>), while polycrystalline silicon targets have uniform and fine grains (grain size ≤50 μm), ensuring stable sputtering rate and film thickness deviation ＜±1%.
3. Precision Dimension and Superior Surface Quality

   Planar targets can be customized into circular (φ50-φ300 mm) and rectangular (maximum 1200×600 mm) specifications with thickness 5-20 mm, dimensional tolerance ≤±0.002 mm and flatness ≤0.001 mm; rotating targets have outer diameter φ50-φ300 mm, length ≤4000 mm and coating thickness uniformity deviation ≤±2%. The target surface is treated by chemical mechanical polishing (CMP) with roughness Ra≤0.003 μm, free of scratches, chipping and micro-defects, ensuring the uniformity and consistency of film deposition.
4. Structural Compatibility and Long Service Life Design

   Bonding with backing targets of oxygen-free copper, molybdenum, titanium and other materials is supported, with a bonding strength ≥35 MPa achieved via diffusion bonding or high-temperature brazing, which greatly improves the heat dissipation performance and mechanical strength of the target. The utilization rate of planar targets can reach 35%-40%, and that of rotating targets is as high as 70%-80%. The service life of a single target is more than 80% longer than that of ordinary silicon targets, suitable for continuous industrial production and high-end R&D needs.

Technical Parameters (Typical Values)

Application Fields

1. Advanced Semiconductor Processes

   Used for depositing polycrystalline silicon gate electrodes, SiO₂ gate dielectric layers, Si₃N₄ passivation layers and silicon epitaxial layers in 7nm-28nm process chips. The ultra-low impurity content can avoid the deterioration of device electrical performance, and the crystal orientation-controllable monocrystalline silicon target can ensure the crystalline quality of the film, suitable for the high-end manufacturing of logic chips and memory chips.
2. High-Precision Optical Coating

   As a core target for optical thin films, it is used to prepare anti-reflection films, high-reflection films and beam-splitting film systems for high-transmittance optical glass, laser lenses and infrared detectors. The high purity and low scattering characteristics can ensure the light transmittance of optical components ≥99% and the refractive index uniformity deviation ≤±0.001, suitable for the manufacturing of high-end optical components in aerospace, precision instruments and other fields.
3. High-Efficiency Photovoltaic Cells

   Used for depositing doped silicon films and passivation contact layers in high-efficiency photovoltaic cells such as TOPCon and HJT. By precisely controlling the doping concentration and film purity, the open-circuit voltage and fill factor of the cell are improved, and the conversion efficiency can be increased by 0.5%-1.0%, adapting to the high-efficiency and thinning development trend of the photovoltaic industry.
4. High-End R&D and Special Devices

   Compatible with laboratory-grade ultra-high vacuum sputtering equipment, it is used for R&D verification of new silicon-based thin film materials, quantum devices and flexible electronic devices. It supports customization of crystal orientation, doping concentration and special structures, accelerating the industrialization process of cutting-edge technologies.

Preparation Process

1. Ultra-Pure Raw Material Preparation: Using electronic-grade polycrystalline silicon as raw material, multiple purifications are carried out by float zone (FZ) method to remove metal, carbon, oxygen and other impurities, obtaining 7N-grade ultra-high purity monocrystalline silicon ingots; polycrystalline silicon target raw materials are purified by chemical vapor deposition (CVD) to obtain 6N-grade high-purity polycrystalline silicon powder.
2. Forming and Densification:
   • Monocrystalline Silicon Target: Cutting silicon ingots into blanks, and eliminating internal defects via HIP to improve density;
   • Polycrystalline Silicon Target: Cold isostatic pressing of polycrystalline silicon powder, and densification under high temperature and pressure via SPS process to obtain a uniform and fine grain structure.
3. Ultra-Precision Machining: Adopting diamond wire cutting, grinding and chemical mechanical polishing (CMP) processes to control the dimensional tolerance, flatness and surface roughness of the target. Monocrystalline silicon targets require crystal orientation calibration and cutting.
4. Backing Target Bonding (Optional): Compositing the silicon target with oxygen-free copper/molybdenum backing target via diffusion bonding to achieve atomic-level bonding in a high-temperature vacuum environment, followed by ultrasonic flaw detection to ensure no bonding defects.
5. Ultra-Clean Quality Inspection and Packaging: Detecting impurity content via ICP-MS, crystal orientation via XRD and dimensional accuracy via laser thickness gauge. All qualified products are cleaned with ultra-pure water and vacuum-sealed in a Class 10 clean room.

Usage and Storage Recommendations

1. Pre-Treatment: Before sputtering, bake in an ultra-high vacuum environment (250-300℃, holding for 4-6 hours) to completely remove surface-adsorbed moisture and organics; avoid touching the target surface with bare hands, and use clean gloves or special fixtures for operation.
2. Sputtering Parameters: A vacuum degree ≥1×10⁻⁵ Pa is recommended, with 99.9999% high-purity argon as the working gas and sputtering power density of 2-4 W/cm². DC or RF sputtering mode is adopted, and parameters are adjusted according to target structure and film requirements to ensure film purity and uniformity.
3. Storage Conditions: Vacuum-sealed and stored in a special anti-static packaging box in a Class 100 clean room environment, with storage temperature 10-30℃ and relative humidity ≤30%. Avoid moisture, dust, chemical corrosion and severe collision. The shelf life is 12 months.