Chapter 3Deposition and PatterningTechnologies 1
3.1. Deposition method
Many deposition techniques have been developed for the realization of thin films. Among them there is sputtering under different variants (direct current (DC), radio frequency (RF) magnetron or not, assisted by ion beam etc.) and pulsed laser ablation for physical depositions, the sol–gel process and metal–organic chemical vapor deposition (MOCVD) for chemical depositions. These different deposition techniques are described in this chapter.
3.1.1. Cathodic sputtering
As highlighted by Grove in 1852, cathodic sputtering is a deposition process by which the material to be deposited is ejected from the surface of a solid (target) bombarded by energetic particles [GRO 52]. An inert gas is introduced into the chamber previously degassed under high vacuum (~10−6 mbar). Argon is the most commonly used inert gas. However, it is possible to add oxygen or nitrogen to make reactive sputtering. Under the effect of a DC voltage, there is an electric discharge and stable plasma is then established. The positive ions of Argon (Ar+) are extracted from this plasma under the action of an electric field, and bombard the target raised to the cathode potential. Thus, particles or agglomerates of particles are ejected, which will then be deposited on the substrate placed at the anode potential (Figure 3.1). The physical mechanisms of sputtering have been widely studied and are reported in numerous works [MCC 91].