The authors report a simple method to significantly enhance the photoluminescence (PL) of SiNx films by incorporating a SiO2 buffer and annealing treatment under N2 protection. Strong visible PL is achieved with annealing temperature above 650°C. Optimal PL is obtained at 800°C. The composition and structure analysis reveal that strong PL is directly related to the content of the Si–O and Si–N bonds in the SiNx films. These bonds provide effective luminescent centers and passivate the interface between Si core and the surrounding oxide.

No abstract

Ti-Si-N-O films were grown by radio frequency reactive magnetron sputtering of a titanium target with nitrogen and silane gases introduced at a temperature of 40°C. X-ray diffraction and X-ray photoelectron spectroscopy results show that Ti-N, Si-N, Ti-Si, Ti-O, Si-O, and Si-N-O compounds are formed. High-resolution-transmission-electron-microscopy reveals that the film consists of Ti-N, Si-N, Ti-Si nanocrystals embedded in an amorphous Ti-O, Si-O, and Si-N-O matrix. This type of microstructure gives rise to very high stability against copper diffusion under bias temperature stressing ͑BTS͒ compared to binary barrier materials. The BTS result shows that Ti 24 Si 12 N 35 O 29 film can effectively block copper ion diffusion for up to 200°C at 0.5 MV/cm.It is now well recognized that future improvements in the performance of integrated circuits will depend heavily on improvements in the efficiency with which circuit elements are interconnected. Use of the Cu interconnects in microelectronic devices require development of barrier layers which can effectively prevent Cu diffusion into dielectric layers and Si substrates under the influence of electrical and thermal stresses. Extensive work in the deposition of TiN barrier film by both sputtering 1,2 and chemical vapor deposition 3,4 have been reported. A common denominator underlying many of the above references is the columnar structure of TiN, typically with a ͑111͒ or ͑200͒ preferred orientation. Such a structure can lead to short-circuit diffusion paths via grain boundaries and result in the failure of the devices. With the down-scaling of devices and more stringent reliability requirements, there is a need for more effective barrier materials. To this end, a class of refractory, ternary nitride materials, such as Ti-Si-N, 5 Ta-Si-N, 6 and W-Si-N 7 have been proposed as candidates for the next generation diffusion barrier in copper/low-k dielectric back-end-of-line device fabrication. 8,9 One of the advantages of these ternary barrier films is attributed to the mixed microstructure which consists of nanocrystalline M-N ͑M = Ti, Ta, W͒ embedded in amorphous matrix ͑Si-N͒.The barrier material that we have investigated is Ti-Si-N-O films which consist of nanocrystals embedded in an amorphous matrix, but the amorphous matrix in this Ti-Si-N-O film is contributed by Ti-O, Si-O, and Si-N-O phases rather than the Si-N phase. It exhibits excellent barrier properties against Cu ion diffusion under biastemperature stress.In this article, we present a process for low-temperature physicalchemical vapor deposition of Ti-Si-N-O barrier films. Film composition, microstructure, and chemical bonding state have been analyzed. The barrier films showed excellent stability against bias temperature stressing ͑BTS͒, which makes them attractive candidates as future generation barrier materials.A 630 nm thick plasma enhanced chemical vapor deposition ͑PECVD͒ SiO 2 layer was first deposited on a p-type silicon substrate using tetraethyl orthosilicate, ͓Si͑OC 2 H 5 ͒ 4 ͔ and oxygen as pre...

No abstract