Negative capacitance transistors with monolayer black phosphorus

Fei Liu,Hong Guo,Yan Zhou,Xiaoyan Liu,Yijiao Wang,Jian Wang

doi:10.1038/npjquantmats.2016.4

Abstract

AbstractQuantum transport properties of negative capacitance transistors (NC-FETs) with monolayer black phosphorus (ML-BP) are theoretically studied. Our calculations show that atomistic thin ML-BP can enhance the amplification effect of the ferroelectric layer, and subthreshold swing is effectively reduced to 27 mV per decade in ML-BP NC-FETs. Device performance can be further improved by increasing the thickness of ferroelectric layer and using thinner or high-k insulate layer. Due to the temperature dependence of ferroelectric layer ML-BP NC-FETs have higher on-state current at low temperature, which is different from that of MOSFETs. By considering the metal–ferroelectric interface layer, our calculations show that the device performance is degraded by the interface. Compared with the International Technology Roadmap (ITRS) 2013 requirements, ML-BP NC-FETs can fulfil the ITRS requirements for high-performance logic with a reduced supply voltage. The new device can achieve very low power delay product per device width at VD=0.3 V, which is just 44% of that in ML-BP FETs.

Highlights

The development of complementary metal-oxide-semiconductor (CMOS) technology in the past half century has followed the Moore’s law[1] to a very good extent
Even though the supply voltage is reduced to 0.3 V, monolayer black phosphorus (ML-black phosphorus (BP)) negative capacitance field effect transistor (NC-FET) can obtain good device is the same as that of FETs, and the NC-FET device can be viewed as a FET connected to a gate voltage ‘amplifier’
Negative capacitance transistor based on 2D material—monolayer black phosphorus is proposed, which combines 2D material—ML-BP

Summary

INTRODUCTION

The development of complementary metal-oxide-semiconductor (CMOS) technology in the past half century has followed the Moore’s law[1] to a very good extent. The combination of the external electric field and the polarisation in the FE material gives rise to a negative voltage drop through the FE layer and, in effect, results in a ‘voltage amplification’ that improves the subthreshold characteristics This possibility of achieving sub 60-mV per decade has excited great interests on NC-FETs.[5,6,7,8,9,10,11] Experimentally, a sub-60 mV per decade has been achieved in polymer FE MOSFETs5 and the capacitance of FE-dielectric bilayer has been enhanced due to the negative capacitance effect.[6] Very recently, a direct measurement of negative differential capacitance has been achieved,[12] and negative capacitance FinFETs have be realised to achieve extremely low-steep swings.[13].

RESULTS

Findings

DISCUSSION

CONCLUSION