X-ray photoelectron spectroscopy of polycrystalline AlN surface exposed to the reactive environment of XeF2

X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM) measurements of polycrystalline AlN surfaces exposed to XeF2 vapor at 1.8x10-4 Torr at sample temperatures ranging from Ts=300 to 920 K are reported. No change in the chemical composition and morphology of the AlN surface exposed at Ts=300 K was observed from a virgin AlN surface. The AlN surface exposed at Ts=700 K is partially fluorinated, forming an AlF3 layer, whereas those exposed at Ts=750 and 800 K are found to be completely covered with an AlF3 layer although no change was observed in morphology. Above Ts=850 K, however, partially fluorinated AlFx (x=1, 2) species and exposed AlN surface area were observed but no AlF3-passivated layer was detected, probably because the AlF3 formed is desorbed as soon as it forms. Therefore, it is concluded that, above Ts=850 K, the fast corrosion reaction of AlN by XeF2 proceeds and thus the AlN surface is strongly etched