Transport Characteristics Of Black Phosphorus Field Effect Transistor And Its Influence On Building Circuit

Black phosphorus is a new two-dimensional semiconductor material discovered in 2014.Due to its direct band gap,it can effectively fill the vacancy between zero-band gap graphene and wide-band gap MoS₂ in two-dimensional materials.In this paper,we will analyze the device structure,transport characteristics,and circuit performance of BP-FET and BP-TFET.The effects of key parameters on the transport properties of BP-FETs are studied by quantum transport theory,non-equilibrium Green's function and Poisson's method.The main research contents include the following aspects:First,the basic transport characteristics of BP-FET,as well as the effects of temperature,device size,and doping concentration on the transport properties of BP-FET were investigated.The results show that with the increase of the gate length of BP-FET,the off-state current of the device becomes smaller,the switching current becomes larger,and the subthreshold characteristics are better improved.When the doping concentration is 0.006 dopant/atom,the device has the highest switching current ratio and lower off-state current;BP-FET has good switching current characteristics in a low temperature environment.Secondly,the transport properties of BP-TFET are studied.The effects of dielectric constant,gate length,temperature and source-drain region doping concentration on the transport properties of the device were investigated and compared with the transport properties of MoS₂-TFET.The results show that when the gate length is 6nm,the BP-TFET has lower off-state current and a higher switching current ratio.When the gate length is larger than this size,no significant change occurs;When the doping concentration is 0.006 dopant/atom,the electrical properties of the device are the best;the BP-TFET achieves the minimum off-state current and the highest switching current ratio at100K.At a temperature of 300K,the BP-TFET has the lowest subthreshold swing close to the ideal value;the on-state current of the MoS₂-TFET is more variable than the BP-TFET by the temperature change,and at the temperature of 300K,The switching current of the device is similar;the on-state current of the BP-TFET is greatly affected by the variation of the gate length.The on-state current of the MoS₂-TFET is larger than the on-state current of the BP-TFET when the gate length is 4 nm and 8 nm.When the dielectric constant is 29,the switching current ratio of the BP-TFET is slightly smaller than that of the MoS₂-TFET.In particular,an asymmetric doping strategy for source and drain regions is proposed.The lower off-state current and higher switching current ratio are achieved by light doping of the drain region,and the physical mechanism is analyzed by potential.Finally,BP-TFETs are applied to a variety of circuits to verify the correctness of their logic functions.In the constructed inverter circuit,the performance of the device is comprehensively evaluated,and the delay,power,PDP are analyzed.It can be found that the PDP is the lowest when the device doping concentration is 0.005 dopant/atom;when the gate length is 10 nm,the device performance can be found to be optimal when combined with power consumption and PDP.