Structure-Property Relationships of Amorphous Hydrogenated Silicon-Carbon Films Produced by Atomic Hydrogen-Induced CVD from a Single-Source Precursor

Abstract

Amorphous hydrogenated silicon±carbon (a-Si:C:H) films were produced by atomic hydrogen±induced (AH) CVD using hexamethyldisilane (HMDS) as a single-source precursor. Radio frequency (rf) hydrogen plasma was the source of atomic hydrogen. The effect of substrate temperature (T s ) on the chemical structure, composition, surface morphology, mechanical properties (dynamic hardness, total stress), and optical properties (refractive index, optical bandgap) of a-Si:C:H film has been examined. Fourier transform infrared (FTIR) spectroscopy and Auger electron spectroscopy (AES) data revealed a drastic drop in hydrogen content in the film, and a rise of the atomic concentration ratio Si/C with increasing T s , thus accounting for the elimination of organic moieties from the film and the formation of a Si±carbidic structure. In the light of scanning electron microscopy (SEM) and atomic force microscopy (AFM) examinations, the films were found to be morphologically homogeneous materials with a maximum size of surface roughness not exceeding 2 nm at T s = 300 C. Both hardness and stress (tensile in nature) are strongly affected by the film composition, their values increasing with rising atomic ratio Si/C. The investigated optical properties of a-Si:C:H film, i.e., refractive index (n) and optical bandgap (E 0 ), can be controlled by the atomic ratio Si/C for a wide range of values: n = 1.58±2.02 and E 0 = 2.3±3.2 eV.

Remote hydrogen–nitrogen plasma chemical vapor deposition from a tetramethyldisilazane source. Part 1. Mechanism of the process, structure and surface morphology of deposited amorphous hydrogenated silicon carbonitride filmsElectronic supplementary information (ESI) available: deconvoluted emission and IR spectra of a-Si–N–C–H films. See http://www.rsc.org/suppdata/jm/b2/b211415c/

“…This means in physical terms, parameter k expresses the mass or thickness of the deposit per unit mass of the source compound fed into the reactor. It is noteworthy, that this parameter is very sensitive to the molecular structure of the source compound and was successfully used in our earlier study for the determination of the reactivity of the organosilicon source compounds in RP-CVD 26,27,[29][30][31][32] and DP-CVD. 34,33 Fig.…”

Remote hydrogen plasma chemical vapor deposition of silicon–carbon thin‐film materials from a hexamethyldisilane source: Characterization of the process and the deposits

“…This allowed us to predict the chemistry of the CVD process, which was determined by the reactivity of the source compound in the atomic hydrogen environment. It is noteworthy that remote hydrogen plasma chemical vapor deposition (RHP‐CVD) has been successfully used for the fabrication of a broad class of technologically important thin‐film materials, including silicon‐based films such as amorphous hydrogenated silicon (a‐Si:H),8–13 silicon carbide (a‐Si:C:H),5, 14–20 silicon nitride (a‐Si:N:H),21, 22 and silicon carbonitride (a‐Si:N:C:H)23 and metal‐based films such as Zn:S:Se,24 Ga:As,25 Cu,26 Ti:N,27 and Ta:N 28…”

Reactivity of Alkylsilanes and Alkylcarbosilanes in Atomic Hydrogen‐Induced Chemical Vapor Deposition

“…Among various chemical vapor deposition (CVD) methods used for the fabrication of a-Si:C:H films, atomic hydrogen-induced chemical vapor deposition (AHCVD) is an extremely attractive technique since it offers well-controlled growth conditions, free of film damaging effects, like charged-particle bombardment or high-energy ultraviolet irradiation.78 Therefore, AHCVD is promising for the production of defect-free, high-quality a-Si:C:H thin-film materials.8- '1 In contrast to other CVD techniques, an advantage of AHCVD is that the process can be initiated in a homogeneous step with contribution of ground-state hydrogen atoms. 8 The atomic hydrogen is effectively generated in the hydrogen plasma and then fed through a remote section to the CVD reactor where its concentration can be determined.7 '8 This allows us to predict and control the chemistry of the CVD process. The use of organosilicon compcn.mds for AHCVD is particularly attractive for the following reasons: they serve as sources of Si-C bonds which are readily incorporated into the deposit, they are easy to convert to film-forming precursors, and they are generally nonexplosive, nonflammable, nontoxic, and inexpensive.…”