Theoretical studies of silicon surface reactions with main group absorbates

Surface chemistry on semiconductor surfaces has gained enormous popularity recently and the interest is still growing. This may be partially due to the tremendous potential of the new functionalities of synthetically modified surfaces. Furthermore, the well-ordered silicon surface, especially Si(100)-2x1, provides a unique environment in which a great deal of existing chemical knowledge can be tested. It is conceivable that, as the size of electronic devices based on crystalline silicon wafers shrinks, the surface characteristics of semiconductor materials become crucial^1,2 for the proper functioning of devices. Thus, the understanding and tailoring of interfacial chemistry of silicon surfaces in particular is increasing in importance. In addition to the traditional modifications of the silicon surface such as etching, doping and film deposition, much attention is being directed to synthetically modified surfaces3 in the pursuit not only of enhanced properties for microelectronics, but other applications including sensors and biologically active surfaces. With the help of traditional organic and organometallic chemistry, a wide variety of new chemically modified silicon surfaces can be synthesized to provide fine tailoring of surface characteristics for a broad range of applications. By studying to what degree our knowledge of organic chemistry may be applied to silicon surfaces, insight into the fundamental characteristic features of surface reactions can be gained. In addition, to gain the control needed to fabricate an organic function into existing semiconductor technologies and ultimately to make new molecule-scale devices, a detailed understanding of the adsorbate surface as well as interfacial chemical reactions and their products at the atomic/molecular level is critical. To accomplish this, both novel experiments and theoretical investigations need to play a significant role in the advance of this emerging field. This chapter begins with a summary of the theoretical methodologies adapted for surface studies and then proceeds to a consideration of the unique features of clean silicon surfaces. Then, the main focus is directed to the structures and reaction mechanisms of organic molecules on silicon surfaces. Surface chemical reactions involving the Si-X interactions (X: various main group elements) are presented focusing on the mechanistic aspects.