Multitechnique elemental depth profiling of InAlGaN and InAlN films

This work shows the capabilities of the plasma profiling time of flight mass spectrometry (PP-TOFMS) for the determination of elemental composition and distribution in InAlGaN thin films used for high electron mobility transistors. The PP-TOFMS results have been compared with wavelength dispersive x-ray fluorescence analyses for the elemental composition determination and with x-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry (TOF-SIMS) for elemental distributions. Relative sensitivity factors have been developed for the comparison of PP-TOFMS with TOF-SIMS results. The PP-TOFMS was able to determine the relative composition of In and Al in the thin films with an accuracy of 10 rel. % without calibration. Depth profiles acquired from the PP-TOFMS technique were obtained within a few minutes and exhibited very similar In, Al, and Ga distributions to TOF-SIMS measurements, and thus PP-TOFMS has been shown to be a valuable addition to TOF-SIMS analysis for a fast process development.