ATOMIC LAYER DEPOSITION (ALD)
Atomic layer deposition (ALD) is a special technique stemmed from CVD technology used to deposit high quality thin films with alternating saturative surface reactions. The difference between other gas phase deposition techniques and ALD is that, the precursor and oxidizing agent vapors are pulsed into the reactor chamber alternately, and the reaction by-products are purged at the end of each step. Hereby, a monomolecular layer of each source vapor is deposited onto the substrate in each step. This results in a unique self-terminating reaction cycle which enables a high conformality, high uniformity and improved control on the process and the thickness of the film. With these advantages, ALD method can meet the demands of scaling down and producing complex three dimension structures especially in electronics industry.