Role of N2 addition on CF4/O2 remote plasma chemical dry etching of polycrystalline silicon
| Autor: | Gottlieb S. Oehrlein, JJ Beulens, B. E. E. Kastenmeier, P. J. Matsuo |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Materials science
Silicon technology industry and agriculture Analytical chemistry chemistry.chemical_element Surfaces and Interfaces engineering.material Condensed Matter Physics Surfaces Coatings and Films Polycrystalline silicon chemistry Ellipsometry Etching (microfabrication) Remote plasma engineering Fluorine Dry etching Reactive-ion etching |
| Zdroj: | Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 15:1801-1813 |
| ISSN: | 1520-8559 0734-2101 |
| DOI: | 10.1116/1.580795 |
| Popis: | The remote plasma chemical dry etching of polycrystalline silicon was investigated using various CF4/O2/N2 gas compositions. The effects of O2 and N2 addition on the etch rate and surface chemistry were established. Admixing O2 to CF4 increases the gas phase fluorine density and increases the etch rate by roughly sevenfold to a maximum at an O2/CF4 ratio of 0.15. The addition of small amounts of N2 (N2/CF4=0.05) can again double this etch rate maximum. Strong changes in surface chemistry were also seen as a result of N2 addition to CF4/O2. Real-time ellipsometry and atomic force micro-roughness measurements reveal that nitrogen addition at low O2/CF4 ratios leads to the smoothing of surfaces, but to increased oxidation at high O2/CF4 ratios. Based on etch rate data and gas phase species analysis, we propose that NO plays an important role in the overall etching reaction. Variable tube lengths separated the reaction chamber from the discharge. These tubes were lined with either quartz or Teflon liners. In ... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|