The influence of interlayer on thermal stress in nanodiamond thin films

Diamond thin film is useful in many applications such as optics, micro-electronics semiconductor and photoelectron. One major problem is the poor adhesion due to thermal stress. Thermal stress comes from the difference in coefficient of thermal expansion (CTE) between the films and the substrate, it is a critical parameter in diamond thin films deposition and especially important for technical applications of nanocrystalline diamond because high thermal stress can lead to cracking or even peel off from the substrate. In this paper, the effect of Si3N4 and SiC interlayer on the thermal stress is calculated, and the influence of thickness on thermal stress is also discussed. The results show that when deposition temperature is lower than 1250K, thermal stress with interlayer in diamond film is smaller than that of without interlayer, this will give the support of some technique parameters for the diamond thin films growth with lower thermal stress.