Analysis of sub-threshold electron transport properties of ultra-scaled amorphous phase change material germanium telluride (invited paper)

The sub-threshold electron transport of ultra-scaled amorphous phase change material germanium telluride is investigated by combining ab-initio molecular dynamics, density functional theory, and non-equilibrium Green's function. The linear and exponential current-voltage curve shapes of the sub-threshold region are captured in the simulations. It is found that the linear current-voltage curve shape is caused by the enlarging of the bias window. It is shown that the exponential current-voltage shape is due to both the bias window enlarging and the bias-induced change of transmission. It is revealed that, in the ultra-scaled device (6 nm channel length), only a very small fraction of the energy carried by the electrons is transferred to the atomic lattice via the inelastic electron-phonon scattering, indicating roughly elastic electron transport in ultra-scaled devices.