摘要
To explore the relationship between the chemical bonding and mechanical properties for germanium carbide (Ge1-xCx) films,the Ge1-xCx films are prepared via reactive magnetron sputtering in a mixture of CH4/Ar discharge,and their composition,chemical bonding and hardness were investigated as a function of substrate temperature (Ts). The results show that Ts remarkably influences the chemical bonding of Ge1-xCx film,which results in a pronounced change in the film hardness. As Ts increases from ambient (60 ℃) to 500 ℃,the Ge content in the film gradually increases,which promotes forming sp3 C-Ge bonds in the film at the expense of sp2C-C bonds. Furthermore,it is found that with increasing Ts the fraction of C-H bonds in Ge1-xCx film gradually decreases,which is attributed to an enhancement in the desorption rate of C-Hn(n=1,2,3) species decomposed from methane. The transition from graphite-like sp2 C-C to diamond-like sp3C-Ge bonds as well as the reduction in C-H bonds in the film with increasing Ts promotes forming the compact three-dimensional network structure,which significantly enhances the hardness of the film from 5.8 to 10.1 GPa.
To explore the relationship between the chemical bonding and mechanical properties for germanium carbide （Ge1-xCx ） films, the Ge1-xCx films are prepared via reactive magnetron sputtering in a mixture of CH4/ Ar discharge, and their composition, chemical bonding and hardness were investigated as a function of substrate temperature （Ts）. The results show that Ts remarkably influences the chemical bonding of Ge1-xCx film, which results in a pronounced change in the film hardness. As Ts increases from ambient （60 ℃ ） to 500 ℃ , the Ge content in the film gradually increases, which promotes forming sp3 C-Ge bonds in the film at the expense of sp2C-C bonds. Furthermore, it is found that with increasing Ts the fraction of C -H bonds in Ge1-xCx film gradually decreases, which is attributed to an enhancement in the desorption rate of C - Hn （ n = 1, 2, 3 ） species decomposed from methane. The transition from graphite-like sp2 C - C to diamond-like sp^3 C-Ge bonds as well as the reduction in C - H bonds in the film with increasing Ts promotes forming the compact three-dimensional network structure, which significantly enhances the hardness of the film from 5.8 to 10. 1 GPa.
基金
Sponsored by the National Natural Science Foundation of China ( Grant No. 50525204 and 50832001)
the special Ph.D. Program ( Grant No.200801830025) from MOE
the "211" and "985" Project of Jilin University, China
the program for Changjiang Scholars and Innovative Research Teamin University
Science Frontier and Cross-disciplinary Innovation Project of Jilin University, China (Grant No. 200903022)
