Performance Analysis of Strained Monolayer MoS${}_2$ MOSFET

Abstract

We present a computational study on the impact of tensile/compressive uniaxial (${\epsilon }_{xx}$) and biaxial (${\epsilon }_{xx}={\epsilon }_{yy}$) strain on monolayer MoS${}_2$ NMOS and PMOS FETs. The material properties like band structure, carrier effective mass and the multi-band Hamiltonian of the channel, are evaluated using the Density Functional Theory (DFT). Using these parameters, self-consistent Poisson-Schrödinger solution under the Non-Equilibrium Green's Function (NEGF) formalism is carried out to simulate the MOS device characteristics. 1.75 uniaxial tensile strain is found to provide a minor (6) ON current improvement for the NMOSFET, whereas same amount of biaxial tensile strain is found to considerably improve the PMOSFET ON currents by 2-3 times. Compressive strain however degrades both NMOS and PMOS device performance. It is also observed that the improvement in PMOSFET can be attained only when the channel material becomes indirect-gap in nature. We further study the performance degradation in the quasi-ballistic long channel regime using a projected current method.