Gas phase and surface kinetic processes in polycrystalline silicon hot-wire chemical vapor deposition

• Published in: Thin solid films Vol. 395; no. 1-2; pp. 29 - 35
• Main Authors: Holt, J.K, Swiatek, M, Goodwin, D.G, Muller, R.P, Goddard, W.A, Atwater, Harry A
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 03-09-2001; Elsevier Science; Elsevier
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Direct simulation Monte Carlo; Exact sciences and technology; Hot-wire chemical vapor deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nucleation kinetics; Physics; Theory and models of film growth; Threshold ionization mass spectrometry; Direct simulation Monte Carlo; Hot-wire chemical vapor deposition; Nucleation kinetics; Threshold ionization mass spectrometry; Silanes; Semiconductor materials; Theoretical study; Polycrystals; Mass spectroscopy; Computerized simulation; Crystal growth from vapors; Experimental study; Hot wire; Precursor; Radicals; CVD; Monte Carlo methods; Surface reactions; Nonmetals; Silicon; Kinetics; Gaseous phase reaction
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(01)01202-0

Experiments and numerical simulations have been conducted to determine critical parameters for growth of polycrystalline silicon via hot-wire chemical vapor deposition. Reactor-scale simulations performed using the Direct Simulation Monte Carlo (DSMC) method have revealed a number of important phenomena such as a sharp drop of 1700 K in the gas temperature from the wire to substrate. The gas-phase reaction of silicon atoms produced on the wire with ambient silane molecules has been studied using ab initio quantum chemical calculations. Results reveal that collisional stabilization of the adduct (H3SiSiH) is unlikely under typical growth pressures, but an energetically favorable, low-pressure pathway has been found that leads to the formation of Si2H2 and H2. Threshold ionization mass spectrometry measurements of radicals have revealed that at the pressure characteristic of growth (2-200 mTorr of 1% SiH4 in He), the radical SiH2 is predominant. Finally, film growth studies reveal that hot-wire-produced atomic hydrogen may preferentially etch amorphous silicon and suppress the formation of small nuclei.