The Study On Fabrication Process And Schottky And Ohmic Properties Of Metal-germanium Contacts

In recent decades,with the rapid development of the integrated circuit manufacturing process and semiconductor technology,the performance of the integrated circuit chips has been continuously improved.But now,the technology of scaling down is facing many problems..Compared with the traditional bulk Silicon,Germanium shows more superiority:the higher carrier mobility,the higher stability of current and the lower power consumption.However,most studies on the metal-Germanium contact focus on Single direction.Some systematic research is needed urgently.In this article,we mainly do research on two aspects.One is the Schottky contact of metal and Germanium.We choose five kinds of metals:Ni?AI?Cr?Pt?Ti,and study Schottky contact of germanium substrates with different doping concentration under different annealing temperature.The results show that the Pt-Ge Schottky junction has the maximum switching ratio,which has five orders of magnitude;Ti-Ge Schottky barrier height is mean maximum.In addition,each kind of metal samples under the annealing temperature of 450 degrees Celsius will have the biggest switch ratio.The other is the ohmic contact of Ni electrodes with germanium substrates of different doping type,doping concentration and doping methods,In the research we find the following points.First,for single crystal germanium substrate,ohmic contact resistivity will reduce as the rise of the doping concentration.The minimum contact resistivity is only 0.61×10-5?·cm2 in this experiment,much samller than the results of others.Second,we increase the doping concentration on germanium substrate by ion implantation,but find that the ion implantation may damage the surface and the contact resistivity will increase.Finally we creatively uses the SOD instead of ion implantation doping and successfully make the p+and n+doped germanium substrate,and Ni electrode forming an ohmic contact successfully with these sample.Although the contact resistivity is relatively large,further research is needed to optimize the way of SOD doping.Finally,on the effects of annealing temperature on metal and germanium substrate Schottky and ohmic contact,we find that the Schottky barrier height and ohmic contact resistivity almost have nothing to do with the temperature.But in Schottky barrier,we find that after annealing of 450? the sample can get the maximum switch ratio.