We present the dynamics and energetics of an Eley-Rideal reaction by which SiH3 radicals impinging on a H-terminated Si(001)-(2 × 1) surface during plasma deposition abstract hydrogen atoms from the surface and return to the gas phase as silane molecules. The reactions were observed during classical molecular-dynamics simulations of hydrogenated amorphous silicon deposition from SiH3 radicals impinging on H-terminated Si(001)-(2 × 1) surfaces maintained at temperatures over the range 500 K ≤ T ≤ 773 K. The H-abstraction reaction introduces dangling bonds at the surface that impinging SiHx (0 ≤ × ≤ 3) radicals can attach to; thus, it is a crucial reaction for deposition. The computed activation energy barrier for the reaction and the exothermic reaction energy are 0.09 eV and 0.23 eV, respectively. The energetics of the reaction as computed based on an empirical classical potential are in good agreement with density-functional-theory pseudopotential calculations using a cluster model.
Bibliographical noteFunding Information:
This work was supported by the NSF/DOE Partnership for Basic Plasma Science and Engineering (Award No. DMR 97-13280), by the Universities Space Research Association with Cooperative Agreement No. NCC 2-1006 (Award No. 8008-001-003-001), and by the National Science Foundation through a NYI award to E.S.A. (ECS 94-57758) and a CAREER award to D.M. (ECS 95-01111). S.P.W. was supported by NASA Contract No. NAS2-14031 to ELORET. Fruitful discussions with D.C. Marra, S.M. Han, L.A. Zepeda-Ruiz, M. Meyyappan, T. Halicioglu, and D. Srivastava are gratefully acknowledged.
- Density functional calculations
- Molecular dynamics
- Plasma deposition
- Plasma processing
- Semiconductor-semiconductor thin film structures
- Surface chemical reaction