The Research Of The InGaZnO Tunnel And Junction Transistors Based On Vertically Stacked BP/InGaZnO Heterojunctions

The rapid development of mobile and internet of thing devices demands continuous scaling of metal-insulator-semiconductor field-effect transistors(MISFETs)for high-resolution and low-power displays.However,such technology is limited by inadequate scaling of supply voltage and sophisticated dielectric engineering.Here,to enable continued scaling,we design and fabricate indium-gallium-zinc-oxide(InGaZnO)tunnel field-effect transistor(TFET)and junctionfield-effecttransistor(JFET)basedonvertically stacked black phosphorus(BP)/InGaZnO van der Waals heterojunctions.By varying BP thickness,BP/InGaZnO heterojunctions can be operated as forward rectifying diode,Zener diode and backward rectifying diode,respectively.Room-temperature negative-differential-resistance behavior with large peak-to-valley ratio of 2.13 and high tunneling current density of 160 m A/mm~2 is obtained in thick-BP/InGaZnO heterojunction,which is comparable to conventional Ge or Si homo-or heterojunctions.On this basis,sub-thermionic subthreshold swing(SS)of 11 m V/dec is achieved in InGaZnO TFET.Meanwhile,the InGaZnO JFET based on thin-BP/InGaZnO heterostructure exhibits good transistor performance of on/off ratio exceeding 10~5,high field-effect mobility of 23.5 cm~2/V·s,negligible hysteresis and improved SS of 83 m V/dec.The BP/InGaZnO heterojunction is possibly the only device architecture so far to realize the amorphous metal-oxide-semiconductors TFET and JFET,thus providing promising pathways for further thin-film transistor technology.The main research content of this thesis is as follows:First,we studied the energy band of BP and InGaZnO through the first computing principle,which preliminarily determined the probability of electron tunneling in the heterojunction.At the same time,the electrical properties of BP and InGaZnO are studied,as well as the characterization of the two materials and the heterojunction.To determine the possibility of electron tunneling at BP/InGaZnO heterojunction,we studied the vertical diode properties of InGaZnO and BP with different thicknesses.Then,the electron tunneling phenomenon was found in the thick-BP/InGaZnO heterojunction.Secondly,we applied the heterojunction formed by thick BP and InGaZnO to the TFET.The negative differential resistance phenomenon was successfully observed in the device,and SS broke through the limitation of thermionic,which reached 11m V/dec.Finally,we applied thin BP and InGaZnO to JFET.According to the research and development results,JFET based on thin-BP/InGaZnO heterojunction has good transistor performance.