fig3 17 with reference to fig3 a trench 12 is etched into the oxide layer 10 by chemical etching reactive ion etching rie or other means of creating a trench in the oxide layer 10 the trench 12 creates an oxide layer 10 having a first upper level 13 and second lower level 15 both first and second levels connected by a sidewall region 11 in fig4 a liner 14 is deposited on the silicon oxide layer 10 the liner 14 can be formed of a material selected from the group including but not limited to tantalum ta titanium ti titanium tungsten tiw titanium nitride tin tungsten silicide wsi 2 tungsten nitride wn or chromium cr the liner 14 is optional but preferred because it serves as an adhesion layer for a later formed ferromagnetic cladding layer 16 fig5 it should be noted that trench 12 may optionally be filled with material used to form the liner 14 or any other subsequent layer and then through etching or abrasion of the structure the trench 12 could be redefined this ensures that each subsequent layer is formed within the trench 12 as depicted in fig5 a ferromagnetic cladding layer 16 is deposited over the liner 14 the ferromagnetic cladding layer 16 can be formed from a variety of materials including but not limited to nickel iron ni u2014 fe cobalt iron co u2014 fe cobalt nickel iron co u2014 ni u2014 fe iron fe nickel ni cobalt co or other highly permeable materials the ferromagnetic cladding layer 16 provides a closed magnetic path flux closure around a.