Si (110) Substrate On Nickel Silicide Formation,

As CMOS IC fabrication technology continuously progresses toward nano nodes. The self-aligned silicide (SALICIDE) material and technology also require corresponding innovations. Recent studies show that Nickel mono-silicide (NiSi) has lower resistivity, smaller silicon consumption and lower forming temperature. So afer the application of T1S12 and CoSi2, NiSi is considered as the most potential silicide for the fabriication of high performance CMOS device with aligned structure. Besides, a technology based on a Si (110) surface has been reported. It has been reported that the hole mobility in the channel on a Si(110) surface is largest compared with any other surface. This means that, with this technology, it is possible to increase the current drivability without changing the material and the device structure.The study of the solid phase reaction of ultra-thin Ni film on various Si substrates:When samples with 25 nm ultra-thin Ni film were annealed in different temperatures, NiSi on Si (110) substrate shares many characteristics with Si (100) samples in the relationship between sheet resistance and formation temperature. However, due to a different reaction surface for Si (110) substrate, the formed NiSi may have a different texture from that of (100) surface. The XRD results show that samples on Si(110) and Si(100) substrates have different nickel silicide phases at the same annealing temperature. It demonstrates that NiSi formation on Si (110) substrate requires a higher annealing temperature, because of Si (110) surface's different lattice structure, the interfacial layer with NiSi has different texture from that of Si(100) surface. Since larger grain needs much more energy to change phase, the NiSi formation temperature on Si(110) is higher than that on Si(100).Investigation of contact electricity properties of ultra-thin Ni film on substrates with different orientations substrate:through the investigation of I-V characters of 10 nm ultra-thin Ni film on substrates with different orientations after two-step annealing, we find out that, when annealing the Ni/Si structure samples, the growth of Ni silicide is diffusion-controlled, and Ni is the dominant diffusing species (DDS) for both N12Si and NiSi formation. When Ni and Si form Ni2Si, DDS Ni must penetrate into the Si lattice through, however, in this course, Ni atom diffuses through different interstices on different surfaces:the interstice on Si(100) is like a square, while the one on Si (110) like a hexagon. The interstitial areas are also different。Obviously, it is easier for Ni atom to pass through larger interstice than smaller one. So, Ni has a higher diffusion coefficient on Si (110) than on Si (100), which results in a larger Ni2Si for Si(110) sample. When Ni2Si is transformed to NiSi, still as the DDS, Ni atom should diffuse through Ni2Si to reach the Si and to form NiSi. It can be believed that Si (110) has a higher surface than Si(100) does, which is the main factor of SBH difference. the I-V character of Ni film on Si (110) substrate becomes worse than that of Ni film on Si (100) substrate.