Université Grenoble Alpes, LTM, MINATEC campus, 17 rue des Martyrs, Grenoble Cedex 9, France, Université Grenoble Alpes, CEA-Leti, MINATEC campus, 17 rue des Martyrs, Grenoble Cedex 9, France, Air Liquide Electronics Systems, 8 rue des Méridiens-Sud Galaxie BP 228, Échirolles Cedex, France

We investigated the deposition and the phase-change properties of In-doped GeTe thin films obtained by plasma enhanced metalorganic chemical vapor deposition and doped with indium using a solid delivery system. The sublimated indium precursor flow rate was calculated as a function of sublimation and deposition parameters. Indium related optical emission recorded by means of optical emission spectroscopy during deposition plasma allowed proposing the dissociation mechanisms of the [In(CH3)2N(CH3)2]2 solid precursor. In particular, using an Ar + H2 + NH3 deposition plasma, sublimated indium molecules are completely dissociated and do not induce by-product contamination by addition of nitrogen or carbon in the films. X-ray photoelectron spectroscopy evidences the formation of In-Te bonds in amorphous as-deposited In-doped GeTe films. The formation of an InTe phase after 400 °C annealing is also evidenced by means of X-ray diffraction analysis. The crystallization temperature Tx, deduced from monitoring of optical reflectivity of In-doped GeTe films with doping up to 11 at. % slightly varies as a function of the In dopant level with a decrease of Tx down to a minimum value for an In doping level of about 6-8 at. %. In this In doping range, the structure of crystallized In-GeTe films changes and is dominated by the presence of a crystalline In2Te3 phase. Finally, the Kissinger activation energy for crystallization Ea is showing to monotonically decrease as the indium content in the GeTe film is increased indicating a promising effect of In doping on crystallization speed in memory devices while keeping a good thermal stability for data retention. © 2017 Author(s).

Activation energy, Amorphous films, Carbon, Carbon films, Deposition, Doping (additives), Films, Indium, Light emission, Metallorganic chemical vapor deposition, Nitrogen plasma, Optical emission spectroscopy, Phase change materials, Semiconductor doping, Thin films, X ray diffraction analysis, X ray photoelectron spectroscopy, Crystallization temperature, Deposition Parameters, Dissociation mechanisms, Optical emissions, Optical reflectivity, Phase change property, Precursor flow rates, Product contamination, Vapor deposition