Investigation of Ni-based silicide formation by different dynamic surface annealing approaches
Sub-melt millisecond anneal (MSA) is one of major anneal techniques for forming ultra-shallow and highly activated junctions. Besides post-implant anneal for source/drain and source/drain extensions, MSA has also attracted increased interests in nickel-silicide formation recently. During the silicidation process, desired Ni diffusion in forming silicides is competing with un-wanted Ni diffusion along defects paths. The latter will cause higher junction leakage and/or source/drain leakage. Since the activation energy for the un-wanted diffusion is lower, higher process temperature with shorter duration is beneficial for minimizing the un-wanted diffusion. Furthermore, MSA allows high process temperature to be used for silicide formation, which can re-activate some dopants, such as arsenic and phosphors. These dopants are easily deactivated during lower temperature thermal processes post source/drain formation such as silicide block film deposition; therefore, transistor performance can be improved by using MSA for silicidation processes. In this work, dynamic surface annealing (DSA), which is one form of MSA techniques, was applied to form Ni-based silicides. The impacts of different combinations of soak RTA and DSA for thermal steps before and after selective nickel/NiSi strip were examined. One step DSA has been demonstrated effective reduction of Nickel piping by e-beam inspection count, improved NiSi resistance and junction leakage w/o device performance degradation.
Self-aligned silicides for Ohmic contacts in complementary metal–oxide–semiconductor technology: TiSi2, CoSi2, and NiSi
Metal silicides continue to play an indispensable role during the remarkable development of microelectronics. Along with several other technological innovations, the implementation of the self-aligned silicide technology paved the way for a rapid and successful miniaturization of device dimensions for metal–oxide–semiconductor field-effect transistors (MOSFETs) in pace with the Moore’s law. The use of silicides has also evolved from creating reliable contacts for diodes, to generating high-conductivity current paths for local wiring, and lately to forming low-resistivity electrical contacts for MOSFETs. With respect to the choice of silicides for complementary metal–oxide–semiconductor (CMOS) technology, a convergence has become clear with the self-alignment technology using only a limited number of silicides, namely TiSi2, CoSi2, and NiSi. The present work discusses the advantages and limitations of TiSi2, CoSi2, and NiSi using the development trend of CMOS technology as a measure. Specifically, the reac...
Occupational Therapy Graduate Education: The Scientist-Practitioner Model
The development of a scientific based practice is essential if occupational therapists are to defend their practice against scepticism and budget cuts. In order to equip the profession with the skills necessary to develop a scientific basis for practice, it is generally considered that graduate programs in occupational therapy should be initiated. This paper argues that to be most effective a specific kind of graduate program is required — one based on the scientist-practitioner model. This model provides for the dual education of professionals as clinicians and researchers. In occupational therapy the undergraduate curricula already provide excellent education in clinical interventions. Thus, it is the role of the graduate curricula to provide education in methods of scientific inquiry and their application to clinical practice. The composition of such a curriculum is described.