A method for independent measurement of elastic modulus and Poisson`s ratio of diamond-like carbon films
- Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Thin Film Technology Research Center
- Korea Research Inst. of Standards and Science, Taejon (Korea, Republic of). Materials Evaluation Center
- Yonsei Univ., Seoul (Korea, Republic of). Dept. of Ceramic Engineering
A simple method to measure the elastic modulus and Poisson`s ratio of diamond-like carbon (DLC) films deposited on Si wafer was suggested. This method involved etching a side of Si substrate using the DLC film as an etching mask. The edge of DLC overhang free from constraint of Si substrate exhibited periodic sinusoidal shape. By measuring the amplitude and the wavelength of the sinusoidal edge, the authors can determine the strain of the film required to adhere to the substrate. Combined with independent stress measurement by laser reflection method, this method allows calculation of the biaxial elastic modulus, E/(1 {minus} {nu}), where E is the elastic modulus and {nu} Poisson`s ratio of the DLC films. By comparing the biaxial elastic modulus with plane-strain modulus, E/(1 {minus} {nu}{sup 2}), measured by nano-indentation, they could further determine the elastic modulus and Poisson`s ratio, independently. This method was employed to measure the mechanical properties of DLC films deposited by C{sub 6}H{sub 6} r.f. glow discharge at the deposition pressure 1.33 Pa. The elastic modulus, E, increased from 94 to 128 GPa as the negative bias voltage increased from 400 to 550 V. Poisson`s ratio was estimated to be about 0.22 in this bias voltage range. For the negative bias voltages less than 400 V, however, the present method resulted in negative Poisson`s ratio. The limitation of the present method was discussed.
- OSTI ID:
- 305501
- Report Number(s):
- CONF-971201-; TRN: IM9906%%181
- Resource Relation:
- Conference: 1997 fall meeting of the Materials Research Society, Boston, MA (United States), 1-5 Dec 1997; Other Information: PBD: 1998; Related Information: Is Part Of Thin-films -- Stresses and mechanical properties 7; Cammarata, R.C. [ed.] [Naval Research Lab., Washington, DC (United States)]; Nastasi, M. [ed.] [Los Alamos National Lab., NM (United States)]; Busso, E.P. [ed.] [Univ. of London (United Kingdom). Imperial Coll.]; Oliver, W.C. [ed.] [Nano Instruments, Inc., Oak Ridge, TN (United States)]; PB: 663 p.; Materials Research Society symposium proceedings, Volume 505
- Country of Publication:
- United States
- Language:
- English
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