Plasma Surface Engineering @ ALPS

Lipon - solid electrolyte analysis by GD-OES

Li3PO4Nx is one material currently studied for efficient energy storage. LiPON, as a solid electrolyte (with high ionic conductivity >2.10-6 S/cm) is particularly interesting because it offers the possibility of generating compact 3D structures for high density energy storage. Various plasma processes are currently used and/or studied to produce LiPON layers of sufficient homogeneity and high deposition rate.


Analytical assistance of Glow Discharge Optical Emission Spectroscopy (GD-OES) can guide the optimisation of a plasma deposition process, in this case a Plasma Enhanced CVD Process (Multipolar Microwave Plasma) from Li and P precursos. GD-OES provide rapid content depth profile analysis thin films. GD-OES is used for  the optimisation of a “LiPON plasma” process. The results of GD-OES analysis are compared to results obtained by ToF-SIMS (for the depth resolution) and XPS (for the accuracy). 


Glow Discharge Optical Emission Spectroscopy is a rapid direct analysis technique for surfaces and interfaces of solid materials, both conducting and insulating. GD-OES employs a capacitively coupled low pressure glow discharge, where the sample is used as the cathode and a copper tube is used as anode. The sample material is sputtered by the bombardment of ions and fast atoms. The sputtered atoms diffuse into the negative glow region of the discharge, situated inside the tubular anode. Here they are excited and/or ionised. The subsequent emission of photons allows their detection by means of an optical spectrometer.


Due to the high mobility of the Li+ ions at room temperature, the sample material had to be cryo-cooled during the analysis in order to avoid the migration of the ions during the analytical procedure. This cooling was necessary for both SIMS and GD-OES analysis. The homogenous LiPON layer is clearly revealed in between the two titanium layers. The peculiar oscillation of the lithium intensity is due to a multiple beam interference of photons emitted by the plasma and reflected on the sample surface and photons reflected at the interfaces with the titanium interlayer. This effect is well described and can be corrected and used to obtain further information on the layer and the erosion rate.

Lipon images

deposition reactor

GD depth profile LiPON

SIMS depth profile LiPON

Sample cooling

GD-source design




Already the qualitative depth profiles, simply displaying emission intensities as function of time, provide important information on the deposited layer. The simplicity of the method allows  to measure large number of specimen produced under different plasma deposition conditions. These analytical results, when carefully interpreted and compared to the deposition conditions allow to improve the search for optimal plasma conditions. Only at a later stage a full quantification of the elemental depth profiles is necessary, to validate the chemical composition of the LiPON layers


Université de Toulouse, UPS, INPT, CNRS, LAPLACE (Laboratoire Plasma et Conversion d’Énergie), 118 route de Narbonne, F-31602 Toulouse Cedex 9, FR

Biophy Research S.A, ZAC Saint Charles - 131 Avenue de l’Etoile - 13710 Fuveau, FR


La décharge luminescente comme outil analytique.
L'influence du taux d'émission secondaire sur ses caractéristique

E. Barisone
PhD thesis, Univ Toulouse III, 2011


E.Barisone , G. Girard , G.Tschopp , Th.Nelis , L. Roske , Y. de Puydt , L. Dupuy , P. Raynaud
18th International colloquium on Plasma processes Nantes July 5-8 2011,