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Title: The comparison of the growth models of silicon nitride ultrathin films fabricated using atmospheric pressure plasma and radio frequency plasma

Abstract

The reaction process model during initial nitridation of Si (111) using atmospheric pressure plasma source was constructed and it was compared to that using a radio frequency plasma source. In atmospheric pressure plasma, emission lines from the N{sub 2} second positive system were dominantly observed. By exposing the atmospheric pressure plasma to Si substrate at the temperature ranging from 25 to 500 degree sign C, silicon nitride films with a thickness below 1.8 nm were formed. In order to study the nitridation process, the changes in the film thickness against the substrate temperature and nitridation time were systematically studied at a pressure ranging from 50 to 700 Torr. The film thickness increases with increasing the nitridation pressure below 400 Torr and it saturates above 500 Torr. It was completely regardless of the substrate temperature. From the time dependence of the film thickness at various nitridation pressures, it was revealed that these experimental results were well fitted to a Langmuir-type adsorption model. In the case of nitridation using atmospheric pressure (AP) plasma, molecular species play an important role for nitridation without thermal diffusion. The difference of silicon nitride films fabricated using AP plasma and rf plasma originates from the difference inmore » the active species.« less

Authors:
; ; ; ; ;  [1];  [2]
  1. Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
20982633
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 2; Other Information: DOI: 10.1063/1.2424501; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ADSORPTION; ATMOSPHERIC PRESSURE; COMPARATIVE EVALUATIONS; CRYSTAL GROWTH; CRYSTAL MODELS; DEPOSITION; NITRIDATION; PLASMA; RADIOWAVE RADIATION; SEMICONDUCTOR MATERIALS; SILICON NITRIDES; SUBSTRATES; THERMAL DIFFUSION; THICKNESS; THIN FILMS; TIME DEPENDENCE

Citation Formats

Nakae, Mari, Hayakawa, Ryoma, Yoshimura, Takeshi, Fujimura, Norifumi, Kunugi, Shunsuke, Uehara, Tsuyoshi, and Sekisui Chemical Co., Ltd., 32 Wadai, Tsukuba, Ibaraki 300-4292. The comparison of the growth models of silicon nitride ultrathin films fabricated using atmospheric pressure plasma and radio frequency plasma. United States: N. p., 2007. Web. doi:10.1063/1.2424501.
Nakae, Mari, Hayakawa, Ryoma, Yoshimura, Takeshi, Fujimura, Norifumi, Kunugi, Shunsuke, Uehara, Tsuyoshi, & Sekisui Chemical Co., Ltd., 32 Wadai, Tsukuba, Ibaraki 300-4292. The comparison of the growth models of silicon nitride ultrathin films fabricated using atmospheric pressure plasma and radio frequency plasma. United States. doi:10.1063/1.2424501.
Nakae, Mari, Hayakawa, Ryoma, Yoshimura, Takeshi, Fujimura, Norifumi, Kunugi, Shunsuke, Uehara, Tsuyoshi, and Sekisui Chemical Co., Ltd., 32 Wadai, Tsukuba, Ibaraki 300-4292. Mon . "The comparison of the growth models of silicon nitride ultrathin films fabricated using atmospheric pressure plasma and radio frequency plasma". United States. doi:10.1063/1.2424501.
@article{osti_20982633,
title = {The comparison of the growth models of silicon nitride ultrathin films fabricated using atmospheric pressure plasma and radio frequency plasma},
author = {Nakae, Mari and Hayakawa, Ryoma and Yoshimura, Takeshi and Fujimura, Norifumi and Kunugi, Shunsuke and Uehara, Tsuyoshi and Sekisui Chemical Co., Ltd., 32 Wadai, Tsukuba, Ibaraki 300-4292},
abstractNote = {The reaction process model during initial nitridation of Si (111) using atmospheric pressure plasma source was constructed and it was compared to that using a radio frequency plasma source. In atmospheric pressure plasma, emission lines from the N{sub 2} second positive system were dominantly observed. By exposing the atmospheric pressure plasma to Si substrate at the temperature ranging from 25 to 500 degree sign C, silicon nitride films with a thickness below 1.8 nm were formed. In order to study the nitridation process, the changes in the film thickness against the substrate temperature and nitridation time were systematically studied at a pressure ranging from 50 to 700 Torr. The film thickness increases with increasing the nitridation pressure below 400 Torr and it saturates above 500 Torr. It was completely regardless of the substrate temperature. From the time dependence of the film thickness at various nitridation pressures, it was revealed that these experimental results were well fitted to a Langmuir-type adsorption model. In the case of nitridation using atmospheric pressure (AP) plasma, molecular species play an important role for nitridation without thermal diffusion. The difference of silicon nitride films fabricated using AP plasma and rf plasma originates from the difference in the active species.},
doi = {10.1063/1.2424501},
journal = {Journal of Applied Physics},
number = 2,
volume = 101,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • A detailed structural analysis and dielectric property measurements of silicon nitride films fabricated using atmospheric pressure (AP) plasma were carried out, and the results were compared to those of nitride films fabricated using a radio frequency plasma. Using AP plasma, 1.8-nm-thick silicon nitride films composed of Si{sub 3}N{sub 3.5}O{sub 0.7} were obtained at nitridation temperatures ranging from 25 to 500 deg. C. X-ray photoelectron spectroscopy using a monochromatic Al K{alpha} source at 1486.6 eV and high-resolution Rutherford backscattering spectrometry revealed approximately 10% more nitrogen atoms corresponding to the N-Si{sub 3} bond in the film using AP plasma than those usingmore » rf plasma. In the range of 25-500 deg. C, the nitridation temperature did not affect the leakage current densities of the films fabricated using AP plasma. Films fabricated at 25 deg. C showed leakage current density of as low as 7x10{sup -2} A/cm{sup 2} at 5 MV/cm. This value was one order of magnitude lower than that using rf plasma. The direct-tunneling current simulation analysis with the Wentzel-Kramers-Brillouin approximation revealed that the effective tunneling mass of holes increased due to the nitrogen atoms incorporated in the films. From deep-level transient spectroscopy, signals attributed to defects generated by plasma irradiation in the silicon substrate were not observed.« less
  • Nanocrystalline silicon (nc-Si:H) film deposited on silicon oxide in a very high frequency plasma enhanced chemical vapor deposition with highly H{sub 2} dilution of SiH{sub 4} has been investigated by Raman spectroscopy and high resolution transmission electron microscopy. It is found that at early growth stage the initial amorphous incubation layer in nc-Si:H growth on silicon oxide can be almost eliminated and crystallites with diameter of about 6 to 10 nm are directly formed on the silicon oxide. Nearly parallel columnar structures with complex microstructure are found from cross-sectional transmission electron microscopy images of the film. It is considered thatmore » highly H{sub 2} dilution and higher excitation frequency are the main reason for eliminating the initial amorphous incubation layer in nc-Si:H growth on silicon oxide.« less
  • With a view to fabricating future flexible electronic devices, an atmospheric-pressure plasma jet driven by 13.56 MHz radio-frequency power is developed for depositing Cu thin films on polyimide, where a Cu wire inserted inside the quartz tube was used as the evaporation source. A polyimide substrate is placed on a water-cooled copper heat sink to prevent it from being thermally damaged. With the aim of preventing oxidation of the deposited Cu film, we investigated the effect of adding H{sub 2} to Ar plasma on film characteristics. Theoretical fitting of the OH emission line in OES spectrum revealed that adding H{submore » 2} gas significantly increased the rotational temperature roughly from 800 to 1500 K. The LMM Auger spectroscopy analysis revealed that higher-purity Cu films were synthesized on polyimide by adding hydrogen gas. A possible explanation for the enhancement in the Cu film deposition rate and improvement of purity of Cu films by H{sub 2} gas addition is that atomic hydrogen produced by the plasma plays important roles in heating the gas to promote the evaporation of Cu atoms from the Cu wire and removing oxygen from copper oxide components via reduction reaction.« less
  • Crystallinity thin films of silicon nitride have been grown on a variety of substrates by microwave plasma-enhanced chemical vapor deposition using N[sub 2], O[sub 2], and CH[sub 4] gases at a temperature of 800 [degree]C. X-ray diffraction and Rutherford backscattering measurements indicate the deposits are stoichiometric silicon nitride with varying amounts of the [alpha] and [beta] phases. Scanning electron microscope imaging indicates [beta]--Si[sub 3]N[sub 4] possesses sixfold symmetry with particles sizes in the submicron range. In one experiment, the silicon necessary for growth comes from the single crystal silicon substrate due to etching/sputtering by the nitrogen plasma. The dependence ofmore » the grain size on the methane concentration is investigated. In another experiment, an organo-silicon source, methoxytrimethylsilane, is used to grow silicon nitride with controlled introduction of the silicon necessary for growth. Thin crystalline films are deposited at rates of 0.1 [mu]m/h as determined by profilometry. A growth mechanism for both cases is proposed.« less
  • It is widely accepted that electrode insulation is unnecessary for generating radio-frequency (rf) atmospheric pressure glow discharges (APGDs). It is also known that rf APGDs with large discharge current are susceptible to the glow-to-arc transition. In this letter, a computational study is presented to demonstrate that dielectric barriers provide an effective control over unlimited current growth and allow rf APGDs to be operated at very high current densities with little danger of the glow-to-arc transition. Characteristics of electrode sheaths are used to show that the stability control is achieved by forcing the plasma-containing electrode unit to acquire positive differential conductivity.