C. S. Rafferty

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We have fabricated and demonstrated a new device called the Vertical Replacement-Gate (VRG) MOSFET. This is the first MOSFET ever built that combines (1) a gate length controlled precisely through a deposited film thickness, independently of lithography and etch, and (2) a high-quality gate oxide grown on a single-crystal Si channel. In addition to this(More)
In this work, we first establish the relationship between corner leakage and corner rounding through device simulation. Then, we demonstrate a novel method to produce corner rounding, using a post-CMP, high temperature re-oxidation process (HTR-STI). A semi-empirical model correlating rounding with re-oxidation and nitride mask thickness is derived from(More)
Implanted B and P dopants in Si exhibit transient enhanced diffusion ~TED! during annealing which arises from the excess interstitials generated by the implant. In order to study the mechanisms of TED, transmission electron microscopy measurements of implantation damage were combined with B diffusion experiments using doping marker structures grown by(More)
A thin-film transistor (TFT) with a lightly-doped offset built in the polysilicon gate is proposed. The offset region of the gate acts as a dielectric in the OFF state and as a conductor in the ON state. The unwelcome peak of the electric field near the drain in the OFF state is significantly reduced, as has been confirmed by two-dimensional device(More)
The authors report the implementation of deep-submicrometer Si MOSFETs that at room temperature have a unity-current-gain cutoff frequency (f/sub T/) of 89 GHz, for a drain-to-source bias of 1.5 V, a gate-to-source bias of 1 V, a gate oxide thickness of 40 AA, and a channel length of 0.15 mu m. The fabrication procedure is mostly conventional, except for(More)
The trend of reverse short channel effect (RSCE) with nitrogen implant dose, gate oxide thickness, and threshold implant dose have been measured and simulated. Thinner gate oxide reduces RSCE. Implanting nitrogen also reduces RSCE, but exactly in proportion to gate oxide reduction; no extra effect of the large nitrogen dose was found. Furthermore, a(More)
The increasing use of high energy implantation (HEI) in tub formation, combined with the use of low temperature gate processing, leads to the potential for strong Transient Enhanced Diffusion (TED) effects in the channel profile. We have discovered through simulation and experiment an unexpected saturation of TED broadening in surface profiles. A profiled(More)
Transient diffusion in epitaxial silicon can be suppressed by incorporating high concentrations of carbon. However, the presence of carbon at this level inside the depletion regions of a device leads to increased leakage. We show that a carbon profile tailored to give reduction of transient diffusion (TED) while minimizing carbon concentration in the(More)
We report on fabricated capacitors following B and BF/sub 2/ implantation with near-identical boron profiles as measured by SIMS. The C-V curves showed flatband shifts between the two implanted species which increase with the implant dose, up to 0.27 V for 1e14 cm/sup -2/. Modeling the processing with an interface trap model for boron in the case of BF/sub(More)
A new model of {311} defect evolution is proposed. The defects are characterized by their mean size and their concentration. The flux between free interstitials and {311} defects is described by an expression obtained by extending the classical theory of nucleation. The model is shown to agree well with the experimental data on {311} defect evolution of(More)