Yann Mazel oral presentation (SN2-Tue3-2-1)
Plasma Profiling Time-of-Flight Mass Spectrometry for microelectronics applications
1 CEA-LETI - Université Grenoble Alpes, 17, Avenue des Martyrs, 38054 Grenoble, France
2 Horiba Scientific, Avenue de la Vauve - Passage Jobin Yvon - CS 45002, 91120 Palaiseau, France
Plasma Profiling Time-Of-Flight Mass Spectrometry (PP-TOFMS) is a sputtering-based elemental depth profiling technique combining a pulsed radio-frequency argon plasma source for sample sputtering and ionization with an orthogonal time-of-flight mass spectrometer. Previous studies showed nanometer depth resolution on NiPt-silicides for advanced contacts, calibration-free semi-quantitative profiling on MEMS magnetic stacks and the capacity to simply identify unexpected contaminant .
A PP-TOFMS (Horiba Scientific) has recently been installed in the clean room of the CEA-LETI in close proximity with deposition tools to allow fast feedback on material development. In this work, we use complementary Time-Of-Flight Secondary Ion Mass Spectrometry (TOFSIMS) analyses to evaluate PP-TOFMS relevance on various materials.
The first example is an InAlGaN thin film deposited on GaN used for power applications. PP-TOFMS and TOFSIMS MCs+ analyses are compared as this mode is known to exhibit low matrix effects for III-nitride materials . PP-TOFMS In vs Al direct elemental ratio is consistent with calibrated Wavelength Dispersive X-Ray Fluorescence measurement. When Relative Sensitivity Factors (RSF) are applied to the TOFSIMS measurements, a very good agreement is found between the two techniques (see figure 1).
We also present comparative studies investigating surface depth resolution on delta-layers and dopant sensitivity on Mg doped GaN. Finally, TOFSIMS imaging of PP-TOFMS analysis crater is presented to explain the lower depth resolution generally observed in PP-TOFMS.
 A. Tempez et al., J. Vac. Sci. Technol. B, 2016, 03H120
 P. K. Chu et al, J. Vac. Sci. Technol. B., 1998, 197-203