INVESTIGATION OF THE STRUCTURE AND STABILITY OF THE PT/SIC(001) INTERFACE

Auger electron spectroscopy and low energy electron diffraction have been applied to the study of the structure and thermal stability of the Pt//3-SiC(001) interface. The morphology of the interface appears to be governed by the competition among surface diffusion, intermixing, and chemical reaction. An ultrathin Pt layer (≤8 A thick) deposited on a substrate at low temperature is laterally uniform with some degree of intermixing across the interface. Brief anneals at ≤1000 °C result in aggregation of the Pt into islands interspersed with essentially bare SiC. Higher temperatures lead to reaction of the aggregated Pt to form Pt silicide and release free C. The reaction is signaled by characteristic changes in the Si LVV and C KLL Auger line shapes and by the appearance in LEED of a (2 x 2) pattern (believed to arise from ordered PtSi) and of diffraction rings from oriented polycrystalline graphite. Subsequent deposition of Si and annealing leads to regeneration of SiC by reaction with the free C. These results contrast with those for ultrathin Pt on Si(001) and on α-SiC(0001) which are dominated by the rapid indiffusion of Pt during annealing. A detailed model is presented for the growth and annealing dependence of the Pt//3-SiC(001) interface. © 1990, Materials Research Society. All rights reserved.