Ammonia Decomposition on Silicon Surfaces Studied Using Transmission FTIR Spectroscopy
Abstract
Fourier Transform Infrared (FTIR) transmission spectroscopy was used to monitor the decomposition of NH3 and ND3 on silicon surfaces. Experiments were performed in-situ in an ultra-high vacuum (UHV) chamber using high surface area porous silicon samples. The FTIR spectra revealed that NH3 (ND3) dissociatively adsorbs at 300 K to form SiH (SiD) and SiNH2 (SiND2) surface species. A comparison of the vibrational absorbances for the SiNH2 and Si2NH surface species indicated that the Si2NH species could account for < or = 11% of the surface coverage at 300 K. The infrared absorbances of the SiN-H2 (SiN-D2) scissors mode at 1534 cu cm (1157 cu cm), the Si-H (SiD) stretch at 2077 cu cm (1510 cu cm) and the Si3-N stretches at 930 and 750 cm-1 were employed to monitor the decomposition of the SiNH2 (SiND2) surface species. As the silicon surface was annealed to 700 K, the FTIR spectra revealed that the SiNH2 (SiND2) surface species gradually decomposed to produce Si3N species and additional SiH species. Above 680 D, the SiH surface species decreased concurrently with the desorption of H2 from the porous silicon surface. The uptake of surface species at various adsorption temperature was also monitored as a function of NH3 (ND3) exposure time.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 31, 1990
- Accession Number
- ADA226625
Entities
People
- A. C. Dillon
- A. S. Bracker
- M. B. Robinson
- Paridhi Gupta
- S. M. George
Organizations
- Stanford University