Effect of thermal annealing in H2 atmosphere of SiCxOy films obtained by HFCVD technique

In this work, the effect of thermal annealing in H2 atmosphere on the photoluminescence (PL) of SiC
x
O
y
films is presented. These films were deposited by HFCVD technique at 800° C with 15.6 sccm of H2 flow. After deposition, the samples were annealed at temperatures between 640 and 970° C. After this process, the films were characterized by photoluminescence (PL), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). An increases of PL intensity was observed for annealed sample at 640° C respect to the as deposited sample, although this intensity decreases when the annealing temperature increase to 970° C. The PL response is associated with the radiative defects such as Si-related oxygen deficiency center (Si-ODCs), Si-related oxygen vacancies (Si-NOVs), and non-bridging oxygen hole centers (NBOHCs). The PL behavior could be associated to the increases of radiative defects at 640°C like Si-NOVs and Si-ODCs while at higher temperature there is a decrease of these radiative defect. This PL behavior agrees with the structural change that was correlated with the XPS and FTIR results, specifically the Si-O, Si-O-Si, Si-H, Si-C-H bonds. Also, it was found by AFM that the roughness decreases when the annealing temperature increase due to a network rearrangement process promoted by the temperature and H
2
atmosphere. Finally, we can conclude that the luminescent of SiC
x
O
y
films could be improved with the use of a specific annealing temperature.