A method for forming a T-shaped electrode for a semiconductor structure, comprising: photolithographically forming a first window through a stack of three dielectric layers to expose an underlying surface portion of a substrate, an upper one of the layers having an etch rate higher than an etch rate of a middle one of the layers to a predetermined, first etchant; forming a photoresist layer over the dielectric layers and through said first window onto the exposed surface portion of the substrate ; forming a second window , the second window being in a portion of the photoresist layer in registry with the first window to again expose the surface portion of the substrate with another portion of the photoresist layer being on portions of the upper one of the dielectric layers adjacent to the second window; depositing a metal for forming the T-shaped electrode through the first window and through the second window onto the exposed surface portion of the substrate and onto exposed portions of the upper one of the dielectric layers , portions of the metal being deposited on the said another portion of the photoresist layer , a bottom portion of the metal being juxtaposed sidewalls of the lower one of the dielectric layers forming a portion of the first window; lifting off the photoresist layer from the upper one of the dielectric layers along with the portions of the metal deposited on the said another portion of the photoresist layer; exposing the upper one of the dielectric layers to the first etchant to selectively remove the upper one of the dielectric layers, the etchant stopping at the middle one of the dielectric layers , wherein the upper one of the dielectric layers is silicon oxide or silicon nitride, the middle one of the dielectric layers is aluminum oxide or aluminum nitride, and the lower one of the dielectric layers is silicon oxide or silicon nitride, and wherein the first etchant is SF 6 . photolithographically forming a first window through a stack of three dielectric layers to expose an underlying surface portion of a substrate, an upper one of the layers having an etch rate higher than an etch rate of a middle one of the layers to a predetermined, first etchant; forming a photoresist layer over the dielectric layers and through said first window onto the exposed surface portion of the substrate ; forming a second window , the second window being in a portion of the photoresist layer in registry with the first window to again expose the surface portion of the substrate with another portion of the photoresist layer being on portions of the upper one of the dielectric layers adjacent to the second window; depositing a metal for forming the T-shaped electrode through the first window and through the second window onto the exposed surface portion of the substrate and onto exposed portions of the upper one of the dielectric layers , portions of the metal being deposited on the said another portion of the photoresist layer , a bottom portion of the metal being juxtaposed sidewalls of the lower one of the dielectric layers forming a portion of the first window; lifting off the photoresist layer from the upper one of the dielectric layers along with the portions of the metal deposited on the said another portion of the photoresist layer; exposing the upper one of the dielectric layers to the first etchant to selectively remove the upper one of the dielectric layers, the etchant stopping at the middle one of the dielectric layers , wherein the upper one of the dielectric layers is silicon oxide or silicon nitride, the middle one of the dielectric layers is aluminum oxide or aluminum nitride, and the lower one of the dielectric layers is silicon oxide or silicon nitride, and wherein the first etchant is SF 6 . <EOS>