Patent ID: 7820494

Claim:
A method for forming a component of TMBS type having its periphery formed of a trench with insulated walls filled with a conductor, comprising the steps of: depositing on a semiconductor substrate a thick layer of a first insulating material; depositing a thin layer of a second material; simultaneously digging the peripheral trench and the trenches of the component into the stacking of layers of second and first materials as well as into an upper portion of the substrate, all the trenches having a same width; isotropically etching the first material to remove the portions of the thick layer of the first material between two trenches, whereby the thin layer of the second material only remains in place beyond the peripheral trench and forms a cap overhanging a recess; forming a thin insulating layer on the surface of the portions of the semiconductor layer exposed by the etching step; depositing a layer of a conductive material to fill the trenches and said recess; and etching the layer of the conductive material and the underlying thin insulating layer to expose the surface of said semiconductor layer between two trenches and maintain the conductive material in the trenches and said recess.