Photothermal CVD of Carbon Thin Films using CH₂I₂ as the Precursor

Abstract

Thin carbon films are deposited via CVD from the precursor methylene iodide (CH 2 I 2 ) using two different activation sources; a broadband IR lamp and a thermal plate. Large differences in deposition rates are observed when comparing the two sources of activation. The characteristics of the deposition kinetics of the highly sensitive system are also investigated by employing a split, symmetric reactor, and by using a qualitative model. Raman spectroscopy (RS) is used for microstructural characterization of the films. The lamp technique allows a simple and low-cost experimental setup, for deposition of disordered carbon thin films at relatively low temperatures and high rates.

Novel Nano- and Micro-Processing by Photoactivation of Methylene Iodide Precursor

“…The carbon micro/nano-structures were characterized by scanning electron microscopy (SEM) and micro-Raman spectroscopy. Details of the experimental setup can be found in [15]. Palladium seeds were deposited from a tetra-ammine complex (Pd(NH 3 ) 4…”

“…the temperature discrepancy could then be explained, that in case 1 laser induced temperature act more like the classic CVD heating, as less dissociated species are present. In the CVD case always carbon deposition has been found [13][14][15]. The chemical process itself unfolds huge complexity.…”

“…For example, parallel processing at various UV wavelengths (350, 275/305, 248, 193 nm) resulted in deposition of different forms of carbon [10][11][12]. Employing an IR lamp at perpendicular incidence to the substrate surface, nanocrystalline carbon thin films have been obtained [13][14][15]. The iodine part in the molecule might be regarded as a drawback for proper materials processing.…”

“…The iodine part in the molecule might be regarded as a drawback for proper materials processing. Contrary, it is mainly responsible for its low bond strength, which results in a low thermal activation barrier and a broad spectral activity at high absorption cross sections [15]. Methylene iodide is also a precursor for low cost and low temperature deposition of carbon nanomaterials and for creating interesting features of pulsed laser processing chemistry with respect to nano-technological applications.…”