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Infrared spectroscopy and x-ray diffraction was used to study the growth of microcrystalline silicon films.

Research was conducted to examine the effect of thermal processes on the optical properties, namely, the refractive index, optical gap, Tau coefficient and Urbach energy, of SiN(sub x):H films. Chemical vapor deposition method assisted by an electron cyclotron resonance generated plasma was used to deposit the films with three different nitrogen to silicon ratios. Results demonstrate that the thermal stability of the films depends on starting compositions above and below the percolation threshold for the Si-Si bonds.

The influence of H on the composition and atomic concentrations of Si, O, and N of plasma deposited SiO x N y H z films was investigated. Those samples deposited at higher SiH 4 partial pressures show both Si-H and N-H bonds, while those deposited at lower SiH 4 partial pressures show N-H bonds only. The Si-H and N-H bond concentrations were found to be proportional to the N concentration. The deviation from H-free stoichiometric SiO x N y composition due to the presence of N-H bonds results in an effective coordination number of N to produce Si-N bonds lower than 3. By fitting the experimental composition data to a theoretical model taking into account the influence of N-H bonds, the actual concentration of N-H bonds was obtained, making evident the presence of nonbonded H. The presence of Si-H and Si-Si bonds was found to partially compensate the effect of N-H bonds, from the point of view of the relative N and Si contents. A model was developed to calculate the Si, O, and N atom concentrations taking into account the influence of N-H, Si-H, and Si-Si bonds, and was found to be in perfect agreement with the experimental data measured by HI-ERDA. [ABSTRACT FROM AUTHOR]

The composition, bonding configuration, hydrogen content, and paramagnetic defects of SiO[sub x]H[sub y] thin films were studied. Films were deposited by the electron cyclotron resonance plasma method at room temperature using SiH[sub 4] and O[sub 2] as precursor gases. The film composition was measured by heavy ion elastic recoil detection analysis and energy dispersive x-ray spectroscopy. Suboxide films with compositions ranging from SiO[sub 2] to SiH[sub 0.38] were obtained. Infrared spectroscopy showed the presence of different Si–O and Si–H vibration modes. The usual estimation of the oxygen to silicon ratio by the wave number of the Si–O–Si stretching band was not accurate for films far from stoichiometry. These off-stoichiometric films also showed a broader Si–O–Si stretching peak than the stoichiometric ones, indicating a higher bonding disorder. The position of the Si–O–Si bending and rocking modes did not depend on the film composition. On the other hand, the peak position of the Si–H modes were found strongly dependent on the Si environment. By single-wavelength ellipsometry at λ=632.8 nm the refractive index n was found to range between 1.45 (SiO[sub 2]) and 2.04 (SiO[sub 0.06]H[sub 0.36]). Electron spin resonance measurements showed that stoichiometric films presented the well known E[sup ′] center (·Si≡O[sub 3]) with concentrations in the 10[sup 16]–10[sup 17] cm[sup -3] range, while for Si-rich films (x<1) the Si dangling bond center (Si[sub DB], ·Si≡Si[sub 3]) was the only detectable defect, with concentrations in the 10[sup 18]–10[sup 19] cm[sup -3] range. In near-stoichiometric films both E[sup ′] and Si[sub DB] centers were found. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

SiO[sub x]N[sub y]H[sub z] films were deposited from O[sub 2], N[sub 2], and SiH[sub 4] gas mixtures at room temperature using the electron cyclotron resonance plasma method. The absolute concentrations of all the species present in the films (Si, O, N, and H) were measured with high precision by heavy-ion elastic recoil detection analysis. The composition of the films was controlled over the whole composition range by adjusting the precursor gases flow ratio during deposition. The relative incorporation of O and N is determined by the ratio Q=[lowercase_phi_synonym](O[sub 2])/[lowercase_phi_synonym](SiH[sub 4]) and the relative content of Si is determined by R=[[lowercase_phi_synonym](O[sub 2])+[lowercase_phi_synonym](N[sub 2])]/[lowercase_phi_synonym](SiH[sub 4]) where [lowercase_phi_synonym](SiH[sub 4]), [lowercase_phi_synonym](O[sub 2]), and [lowercase_phi_synonym](N[sub 2]) are the SiH[sub 4], O[sub 2], and N[sub 2] gas flows, respectively. The optical properties (infrared absorption and refractive index) and the density of paramagnetic defects were analyzed in dependence on the film composition. Single-phase homogeneous films were obtained at low SiH[sub 4] partial pressure during deposition; while those samples deposited at high SiH[sub 4] partial pressure show evidence of separation of two phases. The refractive index was controlled over the whole range between silicon nitride and silicon oxide, with values slightly lower than in stoichiometric films due to the incorporation of H, which results in a lower density of the films. The most important paramagnetic defects detected in the films were the K center and the E[sup ′] center. Defects related to N were also detected in some samples. The total density of defects in SiO[sub x]N[sub y]H[sub z] films was higher than in SiO[sub 2] and lower than in silicon nitride films. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Homoepitaxial Si films were prepared by electron cyclotron resonance plasma enhanced chemical vapor deposition on Si(100) substrates at temperatures of 325–500 °C using H[sub 2], Ar, and SiH[sub 4] as process gases. The gas composition, substrate temperature, and substrate bias voltage were systematically varied to study the breakdown of epitaxial growth. Information from ion beam techniques, like Rutherford backscattering and heavy-ion elastic recoil detection analysis, was combined with transmission and scanning electron micrographs to examine the transition from ordered to amorphous growth. The results suggest that the breakdown proceeds in two stages: (i) highly defective but still ordered growth with a defect density increasing with increasing film thickness and (ii) formation of conically shaped amorphous precipitates. The hydrogen content is found to be directly related to the degree of disorder which acts as sink for excessive hydrogen. Only in almost perfect epitaxially grown films is the hydrogen level low, and an exponential tail of the H concentration into the crystalline substrate is observed as a result of the diffusive transport of hydrogen. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The influence of H on the composition and atomic concentration of Si, O, and N of plasma deposited SiO (sub x) N (sub y) H (sub z) film using Fourier-transformed infrared spectroscopy is investigated. A model developed to calculate the expected Si, O, and N concentrations taking in to account the influence of N-H, Si-H, and Si-Si bonds is presented.

The composition, bonding configuration, hydrogen content and paramagnetic defects of SiO(sub x)H(sub y) thin films were studied. The off-stoichiometric films showed a broader Si-O-Si stretching peak indicating a higher bonding disorder.

SiO(sub x)N(sub y)H(sub z) films were deposited from O2, N2, and SiH4 gas mixture at room temperature using the electron cyclotron resonance plasma method. The results show that the total density of defects in SiO(sub x)N(sub y)H(sub z) films are higher than in SiO2 and lower than in silicon nitride films.