THE SURFACE-CHEMISTRY OF HEXAFLUOROACETYLACETONE ON CLEAN AND OXYGEN PRE-COVERED CU(210) - A TEMPERATURE-PROGRAMMED DESORPTION STUDY

The surface chemistry of hexafluoroacetylacetone (Hhfac) on clean and oxygen pre-covered Cu(210) has been investigated by temperature-progra mmed desorption. On the clean surface, the Hhfac decomposes to form te n products desorbing in 13 desorption states, including a CF3COCOCF3 f ragment which could only form via Hhfac disproportionation or polymeri zation. In contrast, on the oxygen pre-covered (oxidized) surface, the re were only six fragments and much simpler chemistry. Some of the Hhf ac is oxidized, while the remainder reacts to form Cu(hfac)(2) at 425 K. Our results show that low-temperature copper etching can occur on a n oxidized Cu(210) surface. However, it is important to keep oxygen on the surface or else polymerization of the Hhfac, and subsequent conta mination will occur. (C) 1998 Elsevier Science B.V. All rights reserve d.