Titanium Target Materials

1. Overview
A target material refers to the material bombarded by high-energy particles during processes such as sputtering deposition. Targets can be classified into metallic, alloy, or oxide types. By changing the target material (e.g., aluminum, copper, stainless steel, titanium, nickel), different thin film systems can be produced, such as ultra-hard, wear-resistant, or corrosion-resistant alloy coatings.

(1) Metallic targets:
Nickel (Ni), Titanium (Ti), Zinc (Zn), Chromium (Cr), Magnesium (Mg), Niobium (Nb), Tin (Sn), Aluminum (Al), Indium (In), Iron (Fe), Zirconium-Aluminum (ZrAl), Titanium-Aluminum (TiAl), Zirconium (Zr), Aluminum-Silicon (AlSi), Silicon (Si), Copper (Cu), Tantalum (Ta), Germanium (Ge), Silver (Ag), Cobalt (Co), Gold (Au), Gadolinium (Gd), Lanthanum (La), Yttrium (Y), Cerium (Ce), Tungsten (W), Stainless Steel, Nickel-Chromium (NiCr), Hafnium (Hf), Molybdenum (Mo), Iron-Nickel (FeNi), etc.

(2) Ceramic targets:
ITO, Magnesium Oxide, Iron Oxide, Silicon Nitride, Silicon Carbide, Titanium Nitride, Chromium Oxide, Zinc Oxide, Zinc Sulfide, Silicon Dioxide, Silicon Monoxide, Cerium Oxide, Zirconium Dioxide, Niobium Pentoxide, Titanium Dioxide, Hafnium Dioxide, Titanium Diboride, Zirconium Diboride, Tungsten Trioxide, Alumina (Al₂O₃), Tantalum Pentoxide, Niobium Pentoxide, Magnesium Fluoride, Yttrium Fluoride, Zinc Selenide, Aluminum Nitride, Boron Nitride, Praseodymium Titanate, Barium Titanate, Lanthanum Titanate, Nickel Oxide, and other sputtering target materials.

2. Key Performance Requirements for Targets

(1) Purity
Purity is one of the most important performance indicators, as it directly affects thin film properties. For example, in microelectronics, wafer sizes have grown from 6" and 8" to 12", while linewidths have shrunk from 0.5 µm to 0.13 µm or smaller. Where 99.995% purity could once meet the needs of 0.35 µm ICs, 0.18 µm lines now require purities of 99.999% or even 99.9999%.

(2) Impurity Content
Solid impurities and absorbed gases like oxygen and water are primary sources of contamination in thin films. Specific industries, like semiconductors, have strict requirements on alkali metals and radioactive elements in aluminum and its alloys.

(3) Density
High density helps reduce porosity in the target, thereby improving sputtering film performance. Density affects not only sputtering rate, but also the electrical and optical properties of the films. Denser targets also better withstand thermal stresses during sputtering.

(4) Grain Size and Distribution
Targets typically have polycrystalline structures. Finer grains tend to improve sputtering rates, while uniform grain size distribution ensures even film thickness during deposition.

3. Material Grades
TA0, TA1, TA2, TA9, TA10, ZR2, ZR0, GR5, GR2, GR1, TC11, TC6, TC4, TC3, TC2, TC1.

4. Applications
Target materials are widely used for decorative coatings, wear-resistant films, and in the electronics industry for CD, VCD, and magnetic disk coatings.

Tungsten-Titanium (W-Ti) Films
W-Ti and its alloys are high-temperature functional coatings with irreplaceable advantages. Tungsten offers a high melting point, strength, and a low thermal expansion coefficient. W-Ti films are characterized by low electrical resistivity, excellent thermal stability, and strong oxidation resistance.

Traditional interconnect metals such as Al, Cu, and Ag are easily oxidized, poorly bonded to dielectric layers, and prone to diffusion into substrates like Si and SiO₂. These behaviors degrade device performance. In contrast, W-Ti alloys serve as excellent diffusion barriers due to their stable thermomechanical properties, low electromigration rate, and superior corrosion and chemical resistance-making them ideal for high-current and high-temperature environments.

5. Development Outlook
W-Ti targets have recently emerged as critical coating materials for photovoltaic cells, especially as diffusion barriers in third-generation solar cells. Thanks to their exceptional properties, the demand for W-Ti targets has surged in recent years. In 2008, global demand reached 400 tons. As the solar industry grows, this figure is expected to rise significantly.

The international solar cell market is expanding rapidly, with 100% annual growth. Many companies-including Germany's Wverthsurlfulcell, the USA's Global Solar Energy, Japan's Honda Showa Solar Shell, and Hitachi Metals-are actively investing in this sector.

China has developed ultra-large, high-density, and high-purity W-Ti targets, a new class of ion-sputtering coating materials. These are widely used as barrier or color-tuning layers in displays, decorative layers in laptops, battery encapsulation, and photovoltaic cell diffusion barriers. Their commercial and economic potential is substantial. Additionally, their production can drive upgrades in China's tungsten industry, increasing product value and global competitiveness.