### Abstract

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, we 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-ν), where E is the elastic modulus and ν Poisson's ratio of the DLC films. By comparing the biaxial elastic modulus with plane-strain modulus, E/(1-ν^{2}), measured by nano-indentation, we 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_{6}H_{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.

Original language | English |
---|---|

Pages (from-to) | 33-38 |

Number of pages | 6 |

Journal | Materials Research Society Symposium - Proceedings |

Volume | 505 |

Publication status | Published - 1998 Jan 1 |

Event | Proceedings of the 1997 MRS Fall Meeting - Boston, MA, USA Duration: 1997 Nov 30 → 1997 Dec 4 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering

### Cite this

*Materials Research Society Symposium - Proceedings*,

*505*, 33-38.

}

*Materials Research Society Symposium - Proceedings*, vol. 505, pp. 33-38.

**Method for independent measurement of elastic modulus and Poisson's ratio of diamond-like carbon films.** / Cho, Sung Jin; Lee, Kwang Ryeol; Eun, Kwang Yong; Han, Jun Hee; Ko, Dae Hong.

Research output: Contribution to journal › Conference article

TY - JOUR

T1 - Method for independent measurement of elastic modulus and Poisson's ratio of diamond-like carbon films

AU - Cho, Sung Jin

AU - Lee, Kwang Ryeol

AU - Eun, Kwang Yong

AU - Han, Jun Hee

AU - Ko, Dae Hong

PY - 1998/1/1

Y1 - 1998/1/1

N2 - 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, we 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-ν), where E is the elastic modulus and ν Poisson's ratio of the DLC films. By comparing the biaxial elastic modulus with plane-strain modulus, E/(1-ν2), measured by nano-indentation, we 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 C6H6 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.

AB - 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, we 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-ν), where E is the elastic modulus and ν Poisson's ratio of the DLC films. By comparing the biaxial elastic modulus with plane-strain modulus, E/(1-ν2), measured by nano-indentation, we 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 C6H6 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.

UR - http://www.scopus.com/inward/record.url?scp=0031643227&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031643227&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:0031643227

VL - 505

SP - 33

EP - 38

JO - Materials Research Society Symposium - Proceedings

JF - Materials Research Society Symposium - Proceedings

SN - 0272-9172

ER -