• Medientyp: E-Artikel
  • Titel: Doping and crystallographic effects in Cl-atom etching of silicon
  • Beteiligte: Ogryzlo, Elmer A.; Ibbotson, Dale E.; Flamm, Daniel L.; Mucha, John A.
  • Erschienen: AIP Publishing, 1990
  • Erschienen in: Journal of Applied Physics, 67 (1990) 6, Seite 3115-3120
  • Sprache: Englisch
  • DOI: 10.1063/1.345388
  • ISSN: 1089-7550; 0021-8979
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  • Beschreibung: Absolute rates for the intrinsic reaction between Cl atoms and surfaces of P-doped polycrystalline silicon, P-doped Si(100) and As, Sb-doped Si(111) substrates were measured for the first time as a function of dopant concentration (Ne) and substrate temperature in a downstream reaction system. This study clearly shows that when there is no ion bombardment, increasing Ne increases the Si-Cl reaction rate even when silicon is lightly doped (∼1015 cm−3), in contrast to in-discharge studies. Moreover, results showed that crystal orientation influences the Cl-Si reaction more than Ne, for Ne<1020 cm−3. The data are fitted to a modified Arrhenius expression, R=νNγenClT1/2e−E/kT, with R the etch rate and nCl the gas phase Cl concentration. The calculated values of the activation energy E are 4.1–4.7 kcal/mole for all doping levels and crystallographic orientations. Therefore, the doping effect is manifested solely in the preexponential (νNγe) of the Arrhenius expression, and the data qualitatively agree with a charge-transfer mechanism which facilitates chemisorption of chlorine.