A study of the nitridation of silicon surfaces by low-energy electron diffraction and auger electron spectroscopy

Low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES) have been used to study the initial stages of the nitridation of silicon. Most of the experiments involved pressures of 10^?5?10^?7 torr of ammonia and silicon temperatures in the range 800–1100°C. An earlier study of the nitridation of the Si (111) surface, has been extended to allow comparison between the (111), (311) and (100) faces of silicon. These surfaces provide a series of unit meshes with different shapes and symmetries while retaining some common geometrical features. Of particular interest for epitaxial theory is the growth of an impurity induced nitride structure, which is common to both Si(111) and Si (311). This may be explained if the nucleation and orientation of the niti ide are determined by the geometry of localised sites, common to both substrates. Subsequent growth of the nitride layer is then dominated by intra-layer bonding, so that the difference in substrate symmetries has little effect.