Nondestructive characterization of a TiN metal gate: Chemical and structural properties by means of standing-wave hard x-ray photoemission spectroscopy

Standing-wave (SW) hard x-ray photoemission (HXPS, HAXPES) is applied to a thick (100 angstrom) film of a metal gate TiN grown on top of a Si/MoSi2 multilayer mirror. The mirror is used to produce a standing wave of 30 angstrom period that is scanned through the sample by varying the x-ray incidence angle over its 1st-order Bragg condition, thus generating rocking curves of various core-level intensities. The thickness and chemical state of the top, oxidized surface of TiN, as well as the buried interface between TiN and the native oxide on top of the mirror are determined by SW-HXPS. The information provided by SW-HXPS is compared to that obtained by XPS Ar+ depth profile. The SW-HXPS method not only does not require destroying the sample but also provides more quantitative results and a more detailed profile of the interfaces than XPS Ar+ depth profile. Various applications of SW-HXPS to nanoscale multilayer semiconductor systems are thus suggested. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4765720]