Impact of a metal-strip on a polarity-based electrically doped TFET for improvement of DC and analog/RF performance

Abstract

To achieve a steep subthreshold slope (SS) and a better \(I_\mathrm{ON}/I_\mathrm{OFF}\) ratio is a major concern for switching applications in semiconductor devices. To overcome these issues, the tunnel field effect transistor (TFET) is a promising device, as it has low leakage current and a low subthreshold slope at room temperature, making it a highly useful device for ultra-lower circuit applications. However, physical doping leads to random doping fluctuations, which is a serious issue in device technology. For this purpose, we report an electrically doped TFET with a metal strip implanted in the oxide layer between the channel/source junction to improve the performance of the device in terms of steep SS and \(I_\mathrm{ON}/I_\mathrm{OFF}\) at very small gate voltage. Furthermore, we have considered the appropriate length and work function of the metal strip to maintain the improved SS and \(I_\mathrm{ON}/I_\mathrm{OFF}\) ratio. The introduction of a metal strip in the oxide layer on a conventional device offers a higher \(I_\mathrm{ON}/I_\mathrm{OFF}\) ratio on the order of \(10^{8}\), steep subthreshold slope (Point \(\hbox {SS} = 8.07\) mV/decade) and significant change in analog/RF performance. The analog/RF figures of merit are observed in terms of transconductance (\(g_{m}\)), gate-to-drain capacitance (\(C_\mathrm{gd}\)), cutoff frequency (\(f_{T}\)), and gain bandwidth product. The proposed device would be very useful for ultra-low power and high frequency circuit applications at low gate voltages. All simulated results are carried out using 2-D ATLAS software.