Implementing expanded source doping to improve performance of a nano-scale fully depleted silicon on insulator transistor

Abstract

IIn this paper, we proposed a short channel Silicon on Insulator Metal-oxide Semiconductor-Field-Effect-Transistor (SOI-MOSFET), in which a thin layer of n+-type doping has been expanded from top of its entire source region into the channel and also a proportionally heavily p-type retrograde doping has been implanted in its channel, close to the source region. Due to source doping expansion in the channel, we call this structure as Source Expanded Doping Silicon on Insulator (SED-SOI) structure. This expanded n+ doping increases the carrier concentration in the source, which can be injected into the channel. Moreover, it increases the amount of carriers, which can be controlled more effectively by the gate electrode. These two advantages enhance both ON state current and transconductance in the device more than 1.9 mA and 5 mS, respectively. Engineered p-type retrograde doping profile causes impurity scattering and this reduces electron mobility in the depth of the device channel, which in turn OFF current decreases down to 0.2 nA. An immense comparison among our proposed device and a conventional structure (C-SOI) shows that it has better performance in terms of Ion/Ioff ratio (>9.5×105), subthreshold swing (75 mV/dec), leakage current, breakdown voltage, hot carrier injection and DIBL. Our analysis demonstrate that SED-SOI transistor can be an excellent candidate for both low power and high performance applications.