Performance Analysis of Ultra-thin-Body, DoubleGate pMOSFETs at 5 nm Technology Node

In this work, quantum ballistic transport study of a Si double-gate pMOSFET has been carried out in an ultra-thin structure. The simulation is performed by using non-equilibrium Green's function (NEGF) solver that incorporates six band k · p model. Based on this framework, we analyze the device characteristics for a channel length of 5 nm considering different transport directions, confinement directions and channel thickness. In the on and off state of the device several physical parameters are necessary for performance analysis including threshold voltage, subthreshold slope, on/off current ratio. Our results confirm that for 5nm gate length, best electrical performance is obtained at (001)/[100] crystal orientation. It is observed that better ON current, subthreshold swing and lower value of tunneling ratio can be achieved by optimizing the channel thicknesses and selecting the proper crystallographic orientation for the device. The I
_ON
/I
_OFF
ratio is also calculated for both high performance and low operating power applications. We find that large channel thickness leads to worse sub-threshold slope due to the stronger source-to-drain tunneling caused by electrostatics degradation. The potential barrier and spectral current density are also presented in order to find the source-to-drain tunneling and ratio for different crystal orientations and body thickness.