Raman studies on nanocomposite silicon carbonitride thin film deposited by RF magnetron sputtering at different substrate temperatures

TL;DR

This study investigates how substrate temperature affects the structural phases and mechanical properties of nanocomposite SiCN thin films, revealing phase transitions and their impact on hardness and modulus.

Contribution

It introduces a modified four-stage Ferrari Robertson model to interpret Raman spectra of SiCN films at different substrate temperatures.

Findings

Transition from sp2 to sp3 carbon with increasing temperature

Crystallite growth of C3N4 and Si3N4 enhances hardness

Reversal to sp2 carbon at 600°C decreases mechanical properties

Abstract

Raman studies of nanocomposite SiCN thin film by sputtering showed that with an increase of substrate temperature from room temperature to 500oC, a transition from mostly sp2 graphitic phase to sp3 carbon took place which was observed from the variation of ID/IG ratio and the peak shifts. This process resulted in the growth of C3N4 and Si3N4 crystallites in the amorphous matrix which led to an increase in hardness and modulus obtained through nanoindentation. However, at a further higher temperature of 600oC, again an increase of sp2 C concentration in the film was observed and the H and E values showed a decrease due to increased growth of graphitic carbon phase. The whole process got reflected in a modified four stage Ferrari Robertson model of Raman spectroscopy.