Lithium Cobalt Oxide (LiCoO2) Sputtering Targets
Purity: 99.9%, Size: 1”, Thickness: 0.125”
Sputtering is a well-established technique used to deposit thin films from a wide range of materials onto substrates of various shapes and sizes. The process using sputtering targets is repeatable and can be scaled from small research and development projects to medium- and large-scale production batches. Chemical reactions may occur on the target surface, during transport, or on the substrate, depending on the process parameters. Although sputter deposition involves many variables, this complexity provides experts with extensive control over film growth and microstructure.
Applications of Sputtering Targets
Sputtering targets are used for film deposition. In this method, thin films are deposited by sputtering, which erodes material from a “target” source and transfers it onto a “substrate,” such as a silicon wafer.
Semiconductor sputtering targets are used for etching when a high degree of anisotropy is required and selectivity is not critical.
Sputtering targets are also used for analytical purposes by etching away target material.
One example is secondary ion mass spectrometry (SIMS), where the target sample is sputtered at a constant rate. As sputtering progresses, the concentration and identity of the ejected atoms are analyzed using mass spectrometry. With the aid of a sputtering target, the composition of the material can be determined, allowing even extremely low impurity concentrations to be detected.
Sputtering also has applications in space. It is one form of space weathering, a process that alters the physical and chemical properties of airless bodies such as asteroids and the Moon.
Lithium cobalt oxide, with the chemical formula LiCoO2, is a dark blue or bluish-gray crystalline solid commonly used as the positive electrode material in lithium-ion batteries.
Miniaturized batteries are of significant interest as portable microelectronic devices and sensors continue to decrease in size. Thin-film batteries can serve as power sources for various low-power electronic devices, including portable electronics and micro-electro-mechanical systems (MEMS), which require very low power and current levels and can therefore be powered by thin-film battery technology.
In battery applications, a magnetron sputtering system can be used. Thin-film lithium layers are typically deposited using conventional sputtering target techniques, in which a LiCoO2 sputtering target assembly—consisting of the LiCoO2 target bonded to a backing plate—is employed to produce the required lithium film. For generating Li thin films, a D.C. (direct current) magnetron sputtering system may be used.
The LixCoyO2 sputtering target is represented by the formula LiCoO2 and forms part of a cathode assembly placed, along with an anode, inside an evacuated chamber filled with an inert gas, preferably argon. Magnets are positioned above the LiCoO2 sputtering target, and a switch connects the target backing plate to a D.C. voltage source. A substrate holder is located below the LiCoO2 sputtering target inside the chamber.
During operation, a high-voltage electric field is applied between the cathode and anode. The inert gas is ionized through collisions with electrons emitted from the cathode. Positively charged ions accelerate toward the cathode and strike the target, dislodging material from its surface. The released material then travels across the chamber and deposits as a LiCoO2 thin film on the substrate, which is typically positioned near the anode.
