A planar transistor for the 32-nm node and beyond with an ultra-shallow junction fabricated using in-situ doped selective Si epitaxy
Shallower junctions must be formed to make transistors work for the 32-nm node. Many kinds of technologies, such as co-implantation, laser spike annealing (LSA), and flash lamp annealing, have been energetically studied to form ultra-shallow junctions. We focused on in-situ doped selective Si epitaxy, with which the short channel effect and the parasitic resistance can be made compatible. Using this epitaxy, ultra-shallow junctions (with effective junction depths (Xj,eff) under 9 nm@5E18) were formed, and 20-nm or shorter PMOS gate transistors were fabricated using the epitaxy
Scalable eSiGe S/D Technology with Less Layout Dependence for 45-nm Generation
We developed a less layout-dependent epitaxially grown SiGe (eSiGe) source/drain (S/D) technique for pFET. We found that the effective stressor region of eSiGe existed only near the channel and that the volume effect of eSiGe was small. On the basis of this mechanism, a new recess RIE and a new epitaxial growth technology were developed, so that the gate-pitch dependence, S/D length dependence and channel width dependence were extremely reduced. In addition, we succeeded in increasing the drive current by improving the eSiGe structure and the impurity profile. We also obtained a high drive current of 750 muA/mum at Vdd=1V, Ioff=100nA/mum
Monte Carlo Study of the Effect of Backscatter Materail Thickness on 99 mTc Source Response in Single Photon Emission Computed Tomography
Introduction SPECT projections are contaminated by scatter radiation, resulting in reduced image contrast and quantitative errors. Backscatter constitutes a major part of the scatter contamination in lower energy windows. The current study is an evaluation of the effect of backscatter material on FWHM and image quality investigated by Monte Carlo simulation. Materials and Methods SIMIND program was used for simulation of a Siemen’s dual-head variable angle scintillation gamma camera. Planar and SPECT scanning of a 99m Tc source and a Jaszczak phantom for varying thicknesses of Perspex slabs, as a backscatter media, were analyzed using the photopeak and scatter windows. Simulated planar images and reconstructed tomographic images were evaluated qualitatively, by two nuclear medicine specialists, and quantitatively, by Structural Similarity (SSIM) Index. Results In the 99m Tc photopeak window, no significant change in total counts due to backscatter material was measured. In the scatter windows, scattering was overestimated compared with a simulated backscatter free SPECT system. For instance, at a thickness of 10 cm, total counts of a 99m Tc source detected in the 72 keV windows eventually doubled with increasing backscatter material, compared with the situation without backscatter material. The backscatter contribution plateaued when more than 7 cm of scatter material was placed but there were optimized results for a backscatter thickness of 4.5 cm. Better image quality for the thickness was confirmed by the results of eye interpretation and also by SSIM algorithm. Conclusion Backscatter should be taken into account, particularly in model-based scatter correction methods in SPECT for an accurate simulation system optimization.