Design and simulation of strained-Si/strained-SiGe dual channel hetero-structure MOSFETs

Abstract

With a unified physics-based model linking MOSFET performance to carrier mobility and drive current, it is shown that nearly continuous carrier mobility increase has been achieved by introduction of process-induced and global-induced strain, which has been responsible for increase in device performance commensurately with scaling. Strained silicon-germanium technology is a hot research area, explored by many different research groups for present and future CMOS technology, due to its high hole mobility and easy process integration with silicon. Several heterostructure architectures for strained Si/SiGe have been shown in the literature. A dual channel heterostructure consisting of strained Si/Si1-xGex on a relaxed SiGe buffer provides a platform for fabricating MOS transistors with high drive currents, resulting from high carrier mobility and carrier velocity, due to presence of compressively strained silicon germanium layer. This works reports the design, modeling and simulation of NMOS and PMOS transistors with a tensile strained Si channel layer and compressively strained SiGe channel layer for a 65 nm logic technology node. Since most of the recent work on development of strained Si/SiGe has been experimental in nature, developments of compact models are necessary to predict the device behavior. A unified modeling approach consisting of different physics-based models has been formulated in this work and their ability to predict the device behavior has been investigated. In addition to this, quantum mechanical simulations were performed in order to investigate and model the device behavior. High p/n-channel drive currents of 0.43 and 0.98 mA/Gm, respectively, are reported in this work. However with improved performance, ~ 10% electrostatic degradation was observed in PMOS due to buried channel device

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