Method for making a high-temperature superconducting field-effect transistor with thick superconducting channel layer

摘要

Disclosed is a method for making a high-temperature super-conducting field-effect transistor with a thick super-conducting channel, the method comprising the steps of depositing a template layer on an oxide crystal substrate by using a pulse laser depositing apparatus; forming a YBa2Cu3O7-x layer on the template layer; patterning the YBa2Cu3O7-x layer to form a patterned YBa2Cu3O7-x layer having an opening and expose a surface portion of the template layer; depositing a YBa2Cu3O7-x channel layer on the surface portion of the template layer and over the patterned YBa2Cu3O7-x layer, the channel layer having a thickness of from 60 to 100 nm; sequentially forming an SrTiO3 protective layer and an SrTiO3 insulating layer on the channel layer; dry-etching back portions of the insulating and protective layers using an etching mask so as to expose surface portions of the channel layer; and forming source/drain electrodes on both the surface portions of the channel layer and at the same time forming a gate electrode on the insulating layer in the opening. In the superconducting FET, the channel layer is formed from 60 to 100 nm in thickness between the substrate and the SrTiO3 layers. Even through the channel layer is affected by the stress-strain up to approximately 25 nm in depth from each surfaces thereof, since total depth of surface regions of the channel layer affected thus is about 50 nm, the channel layer has a super-conducting center region of from 10 to 50 nm in thickness in which a strain is completely eliminated.