| AVS 63rd International Symposium & Exhibition | |
| Novel Trends in Synchrotron and FEL-Based Analysis Focus Topic | Monday Sessions |
| Session SA+AS-MoA |
| Session: | Frontiers of Photoemission with Synchrotron and XFEL Radiation/Advances in High-resolution Imaging Techniques |
| Presenter: | Charlotte Zborowski, CEA, LETI, MINATEC Campus, France |
| Authors: | C. Zborowski, CEA, LETI, MINATEC Campus, France O.J. Renault, CEA, LETI, MINATEC Campus, France E. Martinez, CEA, LETI, MINATEC Campus, France A. Torres, CEA, LETI, MINATEC Campus, France Y. Yamashita, NIMS, Japan G. Grenet, Inl, Ecl, France S. Tougaard, SDU, Denmark |
| Correspondent: | Click to Email |
Recently, the advent of Hard X-ray Photoelectron Spectroscopy (HAXPES) has enabled to study deeply buried interfaces [1]. It was shown that by combining HAXPES with inelastic background analysis [2], structures at a depth >50 nm can be studied. Here, we present a study on technologically relevant High Electron Mobility power Transistors Ta/Al.
The study was performed on stacks of two metal layers of aluminum and tantalum with different thicknesses deposited on an Al0.25Ga0.75N/AlN/GaN heterostructure [Fig. 1a]. We have used the technique to non-destructively study the activation annealing. HAXPES was performed at the Spring-8 synchrotron (Japan) using 8 keV photons.
The figure shows spectra measured around Al, Ga and Ta peaks for an as deposited sample [Fig. 1b]. The calculation of inelastic background was performed using two input parameters; the IMFP, calculated using the TPP-2M formula [3] and as the spectra present marked plasmons, after the elastic peaks, we used an average of individual inelastic cross-sections, σ, which can be determined from reflection electron energy-loss spectra. The calculation of this cross-sections’ average has been made according to a mixtures rule, involving the different crossed layers, which consists in a relevant way to analyze deeply buried layers. The figure shows how the modelling of the inelastic background is used to determine the in-depth distributions, which are found in good agreement with the TEM results. We have also successfully used this technique to study the effect of annealing on the diffusion of the elements at the interfaces.
Bibliography
[1] P. Risterucci et al., Applied Physics Letters 104, (2014).
[2] S. Tougaard, Journal of Electron Spectroscopy and Related Phenomena, 178–179 (2010).
[3] H. Shinotsuka et al., Surface and Interface Analysis 47, 871-888 (2015).
Part of this work was performed at the Nanocharacterization Platform of CEA-MINATEC (PFNC).
NIMS and Spring-8 is acknowledged for providing beamtime and the staff of the BL15-XU beamline for their assistance during the experiment. Cyril Guedj is acknowledged for providing TEM analysis and expertise.