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.

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.