Modeling and Analysis of Parasitic Resistance in Double-Gate FinFETs

A comprehensive model is presented to analyze the three-dimensional (3-D) source-drain (S/D) resistance of undoped double-gated FinFETs of wide and narrow S/D width. The model incorporates the contribution of spreading, sheet, and contact resistances. The spreading resistance is modeled using a standard two-dimensional (2-D) model generalized to 3-D. The contact resistance is modeled by generalizing the one-dimensional (1-D) transmission line model to 2-D and 3-D with appropriate boundary conditions. The model is compared with the S/D resistance determined from 3-D device simulations and experimental data. We show excellent agreement between our model, the simulations, and experimental data.     

BTI characteristics and mechanisms of metal gated HfO/sub 2/ films with enhanced interface/bulk process treatments

Significant deviations in BTI characteristics for metal gate HfO/sub 2/ films compared to silicon oxide based films prove that conventional reliability models based on SiO/sub 2/ films can no longer be directly applied to HfO/sub 2/ based MOSFETS. This study shows the use of conventional accelerated reliability testing in the Fowler-Nordheim tunneling regime to extrapolate time to failure at operating voltages (direct tunneling regime) overestimates device lifetimes. Additionally, unlike conventional gate oxides, the slope of /spl Delta/V/sub t/ versus time (or the rate of charge trapping) in HfO/sub 2/ MOSFETS is dependent on stress voltage. The HfO/sub 2/ based metal gated nMOSFETS show poor PBTI characteristics and do not meet the 10 year lifetime criterion for threshold voltage stability. On the other hand, HfO/sub 2/ based pMOSFETS show superior NBTI behavior and meet the 10 year lifetime criterion. These results are contrary to the observations with conventional gate dielectrics. This paper explores the anomalous charge trapping behavior and provides a comprehensive study of the PBTI characteristics and recovery mechanisms in metal gated HfO/sub 2/ films.     

Modeling early failure in integrated circuit interconnect

A model based on the random electron–atom scattering is developed to characterize the effects of defects and grain sizes on electromigration caused failure in confined sub-micron metal interconnect lines. Our study shows that lines at sub-micron widths with a more uniform microstructure exhibit a greater consistency in time to failure. Taking mean time to failure and dispersion in time to failure as criteria, the simulator predicts that grain sizes in the 0.03–0.05 μm range are optimal for 0.125 μm wide Al alloy lines. We also argue that the early failure mechanism associated with the missing metal defects is eliminated by using a homogeneous, fine-grained material. The uniformity of the structure results in a mono-modal failure distribution and contributes to increasing the built-in reliability of the interconnect lines.     

SiGe-Channel Confinement Effects for Short-Channel PFETs With Nonbandedge Gate Workfunctions

Thin SiGe-channel confinement is found to provide significant control of the short channel effects typically associated with nonbandedge gate electrodes, in an analogous manner to ultrathin-body approaches. Gate workfunction requirements for thin-SiGe-channel p-type field effect transistors are therefore relaxed substantially more than what is expected from a simple observation of the difference between gate and channel workfunctions. In particular, thin-SiGe channels are shown to enable cost-effective high-performance bulk CMOS technologies with a single gate workfunction near the conduction bandedge. Buried channel, gate workfunction, metal gate, SiGe-channel confinement effects, SiGe-channel MOSFET, silicon germanium, ultrathin-body (UTB).