Nondestructive Analysis of Diamond-Like Carbon (DLC) Film Using AIRsight Infrared/Raman Microscope

User Benefits

- The AIRsight Infrared/Raman microscope enables analysis of carbon materials, which cannot be analyzed with an infrared microscope. - Use of the curve-fit function makes it possible to evaluate film quality from various viewpoints, such as the crystallinity and hydrogen concentration of DLC films.

Introduction

Diamond-like carbon (DLC) films are amorphous hard films consisting of carbon and hydrocarbon, and are a material that occupies an intermediate position between graphite, which is characterized by sp² bonding, and diamond, which has sp³ bonding. Because DLC films have a number of excellent features, they are used in all types of familiar products. For example, DLC films are formed on the edge of cutting tools and surface of bearings owing to their excellent wear resistance and low friction property. DLC films are also used on the inner surface of easily-oxidized beverage containers, utilizing their outstanding gas barrier property. Because DLC films are used in such a wide range of applications, the carbon bonding state and hydrogen concentration in the film are adjusted to modify the film properties as required by the intended application. However, when producing or receiving DLC products, it is important to measure and control the bonding state and hydrogen concentration, as these properties may also cause variations in the properties of the film. Raman spectroscopy is used as a quality control technique for DLC films because the bonding state and structure of carbon materials can be captured with good sensitivity. In comparison with X-ray photoelectron spectroscopy (XPS), which is another DLC film analysis method, Raman spectroscopy offers the advantages of simple preparation for measurements and nondestructive measurement with minimal danger of damaging the sample. An example of analysis of a DLC film by XPS may be found in Application News No. K78. The Shimadzu AIRsight Infrared/Raman microscope, which is an integrated instrument including both an infrared microscope and a Raman microscope, supports analysis of various parts and materials, such as carbon materials, with a single instrument. AIRsight not only mutually compensates for the strengths and weakness of infrared spectroscopy and Raman spectroscopy, but also enables highly accurate qualitative analysis by making it possible to measure the same sample by both methods. Moreover, because AIRsight is a microsystem, pinpoint measurement of micro regions of parts that appear externally to be defective and other target positions is possible. This article introduces an example in which the Raman measurement function of AIRsight Infrared/Raman microscope was used to analyze DLC films deposited on silicon wafers.

November 16, 2022 GMT