Electron spectroscopic comparison of the C-rich SiC(0001̄) and Si-rich SiC(0001) surfaces after cleaning and disordering by Ar+ ion sputtering and subsequent annealing is reported. The chemical behavior of the two disordered surfaces differs significantly. Three distinct temperature regions with different carbon surface segregation kinetics are discernible on SiC(0001̄). On SiC(0001) only one temperature region for C-segregation is observed. Below 900 K, no spectroscopic differences between the two crystal surfaces are observed. Between 900 and 1300 K, both faces are terminated by a surface graphite layer and the C-rich face shows an additional carbon surface segregation process. Above 1300 K, the C-terminated surface graphitizes at a higher rate than the Si-terminated surface. Massive graphitization on both surfaces above 1300 K is attributed to Si(g) sublimation from the SiC surfaces. The results demonstrate that extensive surface disordering of polar SiC faces does not destroy the memory for the polarity of the original crystal insofar as high-temperature surface chemistry is concerned.

Methods for studying semiconductor surface chemistry are presented. It is shown that adsorption and desorption kinetic measurements, when combined with Auger spectroscopy, can give useful insights into fundamental elementary surface kinetic processes which are important in understanding the behavior of complex chemical vapor deposition, plasma vapor deposition, or reactive ion etching processes. Techniques for crystal preparation, mounting, temperature control, and reaction kinetic measurements are given using examples from the adsorption and reaction of propylene with Si(100). An illustration of the manipulation of active site availability on Si(100) is described.

A comparison of the kinetics of oxidation at 995 and 1345 K of the SiC(0001̄) and SiC(0001) crystal faces is made. The oxidation rate on the SiC(0001̄) (C-rich face) is higher at both temperatures. SiO2 is formed. At 1345 K, the initial oxidation process is retarded by excess surface carbon. When the excess carbon is volatilized by either CO or CO2 formation, the oxidation rate is higher at 1345 K than at 995 K.

The reaction of Si (100) with C2H4 from a molecular beam source has been studied using x-ray photoelectron spectroscopy, electron-energy-loss spectroscopy, and Auger spectroscopy. Using these methods, we have studied the kinetics of SiC formation under conditions where no gas-phase excitation processes can contribute. At Si (100) temperatures below 940 K, a ‘‘Si-C alloy’’ forms on the surface; annealing to higher temperatures produces SiC exhibiting electron spectroscopic properties identical to SiC (0001). By studies of the characteristic bulk- and surface-plasmon-loss features in the SiC thin film, it has been shown that surface aggregation of bulk Si on top of the growing SiC film occurs at T≥940 K. Under optimum SiC growth conditions, C2H4 yields about 2×10−3 SiC units per C2H4 surface collision on Si (100).

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