Body Current Optimization using Threshold-Voltage-Adjust-Implant Engineering in 45nm SOI MOSFET

Abstract

In this paper, for the first time, Threshold-voltage-adjust-implant is engineered to optimize body current in 45 nm Silicon-on-Insulator (SOI) MOSFET. The peak value and peak position concentration of the Gaussian implant under the gate oxide in the silicon body are varied in order to optimize the body current in SOI technology. The variations affect the devices’ threshold voltages. In order to make a fair comparison, the gate work function is changed to obtain the same threshold voltage within the entire simulated devices and operating regime. The body current is monitored while the it is swept from 0 V to 1.5 V. The maximum of the body current is observed at VDS=1.5 V. The concentration of Threshold-voltage-adjust-implant peak value is changed from 1.7E17 cm-3 to 7E18 cm-3. The peak position of the implant is varied from 0 nm right under the gate oxide to 20 nm below the gate oxide and silicon surface. It is observed that the body current is minimized at the peak value concentration of 7E17 cm-3 and peak position of 0 nm. This can happen by proper choice of the gate work function and gate material. The minimization of body current leads to the less requirement for body contacts and smaller gate parasitic capacitance which, in turn, concludes higher operating frequency and larger fT.