Evaluation of Diamond Like Carbon (DLC)

By Leah Pandiscia, PhD

Download PDF May 4, 2017

  • Industry

  • Technique

Introduction

Raman Spectrometers

DLC Layer 10 nm in Thickness on a Hard Disc

Diamond Like Carbon (DLC) forms an amorphous (non-crystalline) carbon with about twice the hardness of ceramics, and is widely used as a protective film for hard disks and magnetic read heads. Raman spectra are sensitive to disorder changes in crystalline formation and structural modifications in a DLC film. The Raman spectrum of a DLC film consists of two peaks around 1335 cm-1 (D band) and 1550 cm-1 (G band). D band intensity is related to crystalline size, and the intensity ratio, ID/IG, is related to the grain size. The NRS-3000 Series Raman Spectrometer enables rapid DLC measurement with a high signal-to-noise ratio. The optional carbon analysis program simplifies the calculation of peak separation and peak ratio.

NRS-3000 Series
NRS-3000 Series for DLC Evaluation

D-band at 1335cm-1is related to crystallite size, and the intensity ratio of D-band and G-band at 1550cm-1is related to grain size.

Carbon Analysis Program

The Raman spectrum of carbon may change significantly depending on the crystalline structure. In graphite, amorphous carbon, and DLC (diamond-like carbon), in particular, two peak ratios, halfvalue amplitudes, and other factors are used in sample evaluation to determine the degree of crystallization.

About the Author

Leah Pandiscia received her PhD from Drexel University where she studied Biophysical Chemistry. She is a Spectroscopy Applications Scientist at JASCO.