Thermal behavior of the Au/c-Si3N4/Si(111) interface

Photoelectron spectroscopy and low energy electron diffraction have been used to investigate the thermal behavior of the Au/c-Si3N4/Si(111) interface in a temperature range extending from room temperature to 1000 degrees C. The interface consisted of 3.2x10(15) atoms cm(-2) of gold deposited at room temperature on a crystalline silicon nitride layer, which was previously grown on a Si(111) surface. At room temperature, no evidence of any reaction between gold and the substrate has been detected. Between 300 and 400 degrees C, Au-Si reaction takes place. A comparison of the spectra reveals that the Au-Si reaction occurs in the silicon matrix and on top of the nitride layer, due to silicon atom segregation. Nitrogen atoms do not participate in the reaction up to 600 degrees C, at which point a Au-Si-N ternary compound is formed. Subsequently, the silicon nitride desorption begins. Below 600 degrees C, the nitride layer appears to be cracked but not disrupted. In the range of 800-900 degrees C, a root 3 x root 3 pattern was recorded, and finally, gold and nitrogen disappear leading to the 5x1-reconstructed bare Si surface at 1000 degrees C.