Tungsten-titanium (WTi) alloy target

It is a high-performance material widely applied in thin film deposition technology, and WTi alloy thin film is mainly produced by magnetron sputtering (PVD) technology.

1. Characteristics

1) High purity and low impurity

  ・The purity of industrial WTi targets is usually ≥99.9%, high-end semiconductor application requirements ≥99.995%, and even   

     99.999% (e.g. ultra-high purity WTi 10 target).

  -O<500 ppm, C<30 ppm, to reduce thin film defects.

2) High induced density (≧99%)

  ・Heat isostatic pressing (HIP) or vacuum thermo-pressure process is used to ensure a target material with no pores and small   

    crystal grains (<100 μm).

3) Excellent diffusion barrier performance

   ・The WTi alloy thin film can effectively block interdiffusion between the Cu/Al interconnect layer and the Si substrate, preventing 

      circuit damage due to the formation of metal silicides.

    ・Ti (10%~30 wt%) improves intergranular diffusion barrier capability, and W provides low diffusion rate.

4) Low electrical resistivity and high thermal stability

   ・WTi alloys have low electrical resistivity (close to pure W) and are suitable for high current density applications (e.g. power

      devices).

  ・High temperature (>1000°C) resistance and high oxidation resistance make them suitable for high temperature environments 

     such as aero engine coatings.

5) Tunable Components and Microstructure

   ・General composition ratio: W 90 Ti 10 (atomic ratio 70:30), high W content maintains low resistivity properties.

   ・Ti rich phase (β1 phase) content must be controlled, too much of it causes sputtering instability and unevenness of thin film.

2. Main Applications

1) Semiconductor integrated circuits

   ・Diffusion barrier layer: Al/Cu interconnect technology used in processes above 110 nm (e.g., automotive electronic chips).

  ・Contact layer: As a metallization layer in microelectronic devices to improve conductivity and electrical migration prevention performance.

2) Solar cells

   ・As a barrier layer in CIGS thin film solar cells, to improve photoelectric conversion efficiency and long-term stability.

3) Optics and display technology

   ・Low-E (low emissivity) glass coatings, used to enhance thermal insulation and light transmission.

   ・Optimization of conductive layer performance in touch screens (ITO glass).

4) High Temperature and Wear Resistant Coatings

   ・Aero engine parts: High temperature protective coatings (WTi based alloys) such as turbine blades.

   ・Cutting tools :  WTiN coating improves hardness and wear resistance.

5) New application fields

  ・Gas sensors: WTi-O thin film is used for environmental detection.

  ・Electrochromic devices:  WTi-based thin film provides intelligent dimming.