Valence-mended semiconductor surfaces for nanoelectronic applications

Meng Tao



Dangling bonds are an inherent nature of semiconductor surface, and have been an impeding factor to device performance since the Bardeen era. They act as reaction sites in chemical reactions and surface states in electronic processes. Techniques are being developed at UTA to eliminate dangling bonds, and thus surface states, on semiconductor surfaces with an atomic layer of 'valence-mending' atoms. For the Si(100) surface, valence-mending atoms include most of the Group VI atoms: S, Se, and Te. Se passivation of Si(100) has been successfully carried out using molecular beam epitaxy techniques. Monolayer passivation was verified by reflection high-energy electron diffraction and residual gas analysis. The desorption temperature of Se from Si(100) was determined to be between 700-750 C. Various metal contacts on Se-passivated Si(100) have been examined electrically. Schottky barrier heights of metals on Se-passivated Si(100) are significantly different from the decades-old data on barrier heights, but in fair agreement with their ideal barrier heights. Therefore, low Schottky barriers and negative Schottky barriers on n-type Si(100) have been demonstrated. These results have significant implications in terahertz nanoelectronics.



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