Tuning of resistance of nanogaps using field-emission-induced electromigration with feedback control scheme

We report a newly investigated technique for the tuning of tunnel resistance of nanogaps using electromigration phenomena induced by a field emission current, which is called “activation” method. First, Planar-type initial nanogaps of Ni separated by 20-50 nm were defined on SiO₂/Si substrates. Then, a bias current was applied to the initial Ni nanogaps at room temperature using a current source. Here, we propose a feedback approach during activation procedures, in order to precisely control the resistance of nanogaps at room temperature. We call this method “feedback-controlled activation (FCA)”, and it is revealed that control characteristics of tunnel resistance of nanogaps are successfully improved using FCA procedure, as compared with conventional activation without feedback scheme. These results indicate that a feedback approach is useful for the stable control of tunnel resistance of nanogaps using activation method.