Samples of as-deposited iridium and rhodium on single-crystal n-Si were analysed by Auger electron spectroscopy (AES) and electrical methods, together with samples where silicide formation had been induced by heat treatments. The use of AES was found to be advantageous in yielding chemical bonding information as well as atomic concentration data based on the Si LVV line shape and intensity. We report on studies of the deposited layers by AES in conjunction with ion sputtering, focusing on the metal-silicon or silicide-silicon interfaces. The results of these studies can indicate the extent of silicide formation and provide insight into the transition from silicon to silicide. The compositional analysis results are compared with literature values, and their implications for existing models are discussed. The similarities of both systems in their electrical and compositional characteristics and their correlations are pointed out. Observations of silicon segregation at some silicide surfaces are also reported.