The Adsorption and Thermal Composition of N2H4 and CH3N2H3 on Si(111)- 7x7
Abstract
The adsorption and thermal decomposition of N2H4 and CH3N2H3 on Si(111)-7x7 were investigated using XPS, UPS, and HREELS in the 120-1350 K surface temperature range. both molecules were partially dissociated into N2Hx of CH3N2Hx (x=2,3) species with the N-N bond parallel or nearly parallel to the surface as they adsorbed on the surface at 120 K, especially at lower dosages (e.g., < 0.2 L) and more so for N2H4 than CH3N2H3. This was evidenced by the appearance of the Si-H vibration at 255 meV in the HREEL spectra and by the relatively larger FWHMs of the N1s XPS and the n+,n- molecular UPS peaks. When a about 0.4 L N2H4 or CH3N2H3 dosed sample was annealed to about 500 K, significant desorption of the molecules occurred as well as further dissociation of the N-H bonds. Above about 600 K, the N-N bond began to break leading to the formation of NHx (x=1,2) species for both molecules. At about 730 K, the C-N bond dissociated to form CHx on the surface in the case of CH3N2H3. Further annealing of the sample caused complete cracking of the N-H and C-H bonds until Si3N4 or a mixture of Si nitride and Si-carbide were formed for N2H4 or CH3N2H3, respectively.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1991
- Accession Number
- ADA245638
Entities
People
- D. W. Shinn
- Lin Ming-chang
- Yuheng Bu
Organizations
- Emory University