Simulation of Reconfigurable Field-effect Transistors: Impact of the NiSi2-Si Interfaces, Strain, and Crystal Orientation

Reconfigurable transistors (RFETs) can be switched between electron and hole current by changing the polarity of the gate potential. The device performance of such a transistor is strongly dominated by the contact physics.
In this work, the electron transport across the NiSi2-Si interface is studied using the NEGF formalism and density functional theory. A new model is presented which relates the electron transport through the interface to the transfer characteristic of an RFET. The model is compared to experimental data showing good agreement.
Based on the model, the influence of strain and the choice of the crystal orientation is discussed. It is demonstrated that best symmetry between electron and hole current is achieved for the <110> orientation. Furthermore, this symmetry can be tuned by strain, which is not possible for the <100> and <112> orientations. A discussion of these differences based on band structure analysis will be given, too.