Analog/RF Performance of Triple Material Gate Stack-Graded Channel Double Gate-Junctionless Strained-silicon MOSFET with Fixed Charges

Suddapalli Subba Rao,Nistala Bheema Rao,D. Srikar,Rani Deepika Balavendran Joseph,Gopi Krishna Saramekala,Vijaya Durga Chintala

doi:10.1007/s12633-021-01462-0

Abstract

In this paper, analog/radio frequency (RF) electrical characteristics of triple material gate stack-graded channel double gate-Junctionless (TMGS-GCDG-JL) strained-Si (s-Si) MOSFET with fixed charge density is analyzed with the help of Sentaurus TCAD. By varying the various device parameters, the analog/RF performance of the proposed TMGS-GCDG-JL s-Si MOSFET is evaluated in terms of transconductance-generation-factor (TGF), early voltage, voltage gain, unity-power-gain frequency (fmax), unity-current-gain frequency (ft), and gain-transconductance frequency product (GTFP). The results confirm that the proposed TMGS-GCDG-JL s-Si MOSFET has superior analog/RF performance compared to gate stack-graded channel double gate-junctionless (GS-GCDG-JL) s-Si device. However, the proposed MOSFET has less transconductance and less output conductance when compared with the GS-GCDG-JL s-Si device in above threshold region, and reverse trend follows in sub-threshold region.

Highlights

FET is evaluated in terms of transconductance-generation- rial
The results confirm that the proposed TMGS-GCDG- vice operates in nano-scaled regime, fixed charges are JL s-Si MOSFET has superior analog/RF performance created at Oxide/s-Si (SiO2/s-Si) interface due to the compared to gate stack-graded channel double gate- lateral electric field in s-Si MOSFETs [8]-[9]
TFP of the proposed TMGS-GCDG-JL s-Si MOSFET is more than the GS-GCDG-JL s-Si MOSFET in above subthreshold region, and reverse trend follows in weak inversion region

Summary

Proposed MOSFET structure and TCAD setup

Since the strain is developed into silicon channel, the energy-band diagram of the silicon material is affected because of the biaxial-tension. The changes in energy band gap, electron affinity, and effective masses of carrier in s-Si material are formulated as shown below [24, 25]. ≈ 0.075X where VT denotes the thermal voltage, NV,Si and NV,s−Si represent density of states in the valence band, m∗h,Si and m∗h,s−Si denote the effective masses of hole in silicon and strained-silicon, respectively. Both flat band voltage and barrier potential of the source (drain) to channel decrease simultaneously [26]. The proposed device with the fixed charges is simulated using the TCAD [27].

10-2 Line : Sentaurus Symbol : Experimental

Result analysis

Conclusion