Study On In InAs/GaSb Heterogeneous Tunnel Junction

With shrinking of the feature size of semiconductor device,the problem of power consumption is becoming more and more serious due to issues such as Fermi tailing in CMOS technology.There has been a surge of interest in the subthreshold swing of TFET based on the mechanism of BTBT,whose subthreshold swing breaks through the limit of 60m V/dec.However,Si-based TFET has the disadvantage of low on-state current.Extremely high tunneling probability and on-state current are achieved based on the heterogeneous tunneling junction formed by the combination of InAs/GaSb broken band structure,which is the research object of this article.Through the investigation of the research status at home and abroad,it is found that the current research of InAs/GaSb heterogeneous tunnel junctions still has some inadequacy such as the mechanism of the influence of key parameters on the tunneling characteristics is not clear,the high-quality interface matching epitaxial technology needs further exploration,and the regular pattern of the influence of interface defects on the tunneling process is still not sure.In view of the above-mentioned research background and current research situation,implemented a simulation study on the pivotal parameters and interface defects related to the InAs/GaSb heterogeneous tunnel junction,and successfully fabricated the InAs/GaSb heterogeneous tunnel junction.The work carried out in this paper mainly includes:(1)Established and perfected the material model of InAs and GaSb and the simulation model of InAs/GaSb heterogeneous tunnel junction through TCAD Sentaurus simulation software,and then studied the influence of electrical characteristics on InAs/GaSb heterogeneous tunnel junction around the three different pivotal parameters of doping concentration,InAs layer thickness and temperature in the way of simulation and analysis,which provided the theoretical support for the proposal of subsequent material growth structure and analysis of experimental research.Considering the existence of strain accumulation and material inhomogeneity during the material growth process,it is aimed at the effect of the defect density,the location of the energy level of the interface defect and the type of the interface defect on the electrical characteristics of the InAs/GaSb heterogeneous tunnel junction,which can improve the theoretical research of the influence of interface defects on the heterojunction of InAs/GaSb with a broken band structure.Because the current is high before the tunneling of the InAs/GaSb heterogeneous tunnel junction,which is very unfavorable to the off-state characteristic of TFET,the composition of InAs and GaSb related ternary compounds In Ga As and Ga As Sb is adjusted to optimize the energy band structure and improve the device performance on the basis of realizing lattice matching.(2)Using molecular beam epitaxy(MBE)to epitaxial the InAs/GaSb functional layer on the GaSb substrate,the grown epitaxial material was physically characterized by AFM,HRXRD,and XPS,and the results showed that epitaxial material possessed smooth and uniform surface and great lattice quality.On this basis,an InAs/GaSb heterogeneous tunnel junction was fabricated.According to the test results,the specific contact resistivity of the InAs is4.93×10^-6?·cm²,and the specific contact resistivity of the GaSb is 3.28×10^-6?.·cm²,which revealed that the ohmic contact quality fully meets the requirements of device performance,and the tunneling current can reach 1500 A/cm² under reverse bias voltage of 0.8 V.