Thermal reactions of fluorine and nitrogen trifluoride with silicon(110) studied by laser ionization mass spectrometry
| Autor: | J. A. Dagata, David S. Y. Hsu, D. W. Squire, Ming-Chang Lin, C. S. Dulcey |
|---|---|
| Rok vydání: | 1988 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry. 92:2827-2834 |
| ISSN: | 1541-5740 0022-3654 |
| Popis: | The techniques of laser and electron ionization mass spectrometry have been employed to study the thermal etching of Si(110) by F/sub 2/ and NF/sub 4/ at substrate temperatures between 300 and 1200 K. By two-photon resonance-enhanced ionization of SiF/sub 2/ via the B/sup 1/ tilde B/sub 2/ state, the apparent activation energy for gaseous silicon difluoride production was found to be 8.9 +/- 0.3 and 22.1 +/- 1.7 kcal/mol for F/sub 2/ and NF/sub 3/, respectively. SiF was not detected. An extensive search for SiF/sub 3/ during etching by F/sub 2/ at 1000 K, by means of resonance ionization from 320 to 325 and from 416 to 510 nm, also showed no signs of the species. Both SiF and SiF/sub 3/ are thermochemically unimportant etch products under the conditions employed. In F/sub 2/ etching, SiF/sub 4/ and total silicon fluoride ..sigma.. SiF/sub x//sup +/ signals as measured by electron ionization rose rapidly at lower temperatures and stabilized between 700 and 900 K before rising again. No such behavior was observed for SiF/sub 2/ production from F/sub 2/ or for the products formed in NF/sub 3/ etching. Apparent activation energies for total silicon fluoride and SiF/sub 4/ production are similar. Formore » F/sub 2/, they were found to be about 9 kcal/mol in the low-temperature region, and for NF/sub 3/ both were measured to be about 21 kcal/mol. A proposed reaction mechanism explaining these and related results is discussed.« less |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|