We have used three-dimensional simulation to investigate application of a new body contact to (SOI) devices. Performance characteristics of the new body contact on high-voltage (SOI) devices were studied. Our comparative investigation showed increased current drive, improved cutoff frequency, reduced on-resistance while attaining satisfactory breakdown voltage. The new body contact is applicable to both high and low voltage (SOI) MOSFETs.

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 occurs by proper choice of the gate work function and gate material. The minimization of body current leads to the less requirement for the number of body contacts and smaller gate parasitic capacitance which, in turn, concludes higher operating frequency and larger fT.

In this paper for the first time, a circuit model for multi-finger I-gate body-contacted Silicon-on-insulator MOSFET is presented. The model parameters are adjusted using simulation of a 45 nm (SOI) nMOSFET. Using the model, typical body voltage for a 35 finger device is obtained and applied to the transistor. The threshold voltage and drain current are obtained for the first transistor and center ones in the multi-finger structure. The drain induced barrier lowering of the center transistor is increased by 30% and off-current 40 times than that of the first transistor. Simulation results verified the I-gate body contact model in lack of controlling the body voltage comparing with the conventional body contacts e.g. H-gate.