Process for obtaining a thin, insulating, soft magnetic film of high magnetization, corresponding film and corresponding integrated circuit

Abstract

A thin soft magnetic film combines a high magnetization with an insulating character. The film is formed by nitriding Fe-rich ferromagnetic nanograins immersed in an amorphous substrate. A selective oxidation of the amorphous substrate is then performed. The result is a thin, insulating, soft magnetic film of high magnetization. Many types of integrated circuits can be made which include a component using a membrane incorporating the above-mentioned thin film.

1 . A thin, insulating, soft magnetic film of high magnetization, comprising an oxidized amorphous substrate in which nitrided Fe-rich ferromagnetic nanograins are immersed. 
     
     
         2 . The film according to  claim 1 , wherein the nanograins constitute a crystalline phase of FeXN with X being selected from the group of elements consisting of: Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W, Ir, Pt, Al, Si, Ti, V, Cr, Mn, Cu and the lanthanides. 
     
     
         3 . The film according to  claim 1 , wherein the nanograins have a diameter of less than 10 nm. 
     
     
         4 . The film according to  claim 1 , wherein the nanograins have a body-centered cubic or body-centered tetragonal structure. 
     
     
         5 . The film according  claim 2 , wherein the amorphous substrate essentially consists of XO or XNO. 
     
     
         6 . The film according to  claim 1 , wherein an amorphous phase represents less than 20% of the total volume of the thin film. 
     
     
         7 . The film according to  claim 1 , characterized in that each of a plurality of elements is present within the film, in the following proportions in atomic percent: Fe a X b N c O d ,
 45%≦a≦90%,   1%≦b≦5%   5%≦c≦20%   5%≦d≦30%   
       with a+b+c+d=100%. 
     
     
         8 . An integrated circuit, comprising at least one component using a membrane incorporating a thin, insulating, soft magnetic film of high magnetization, comprising an oxidized amorphous substrate in which nitrided Fe-rich ferromagnetic nanograins are immersed. 
     
     
         9 . The integrated circuit according to  claim 8 , wherein the component is an inductive component. 
     
     
         10 . The integrated circuit according to  claim 9 , wherein the membrane of the inductive component can be moved so as to vary the inductance of the component. 
     
     
         11 . The integrated circuit according to  claim 10 , wherein the magnetic film of the membrane has a high magnetic permeability μ′ and low magnetic losses μ″. 
     
     
         12 . The integrated circuit according to  claim 9 , wherein the membrane of the inductive component is fixed and forms a screening cover for the inductive component. 
     
     
         13 . The integrated circuit according to  claim 12 , wherein the magnetic film of the membrane has a low magnetic permeability μ′ and high magnetic losses μ″. 
     
     
         14 . The integrated circuit according to  claim 9 , wherein the membrane of the inductive component incorporates a magnetic film of the FeHfNO type. 
     
     
         15 . The integrated circuit according to  claim 8 , wherein the membrane forms a cover for encapsulating the component. 
     
     
         16 . The integrated circuit according to  claim 8 , wherein the membrane forms a support for the component. 
     
     
         17 . The integrated circuit according to  claim 8 , wherein the component is a capacitive component and in that the membrane forms the dielectric of the capacitive component. 
     
     
         18 . The integrated circuit according to  claim 8 , wherein at least two different components use two different parts of the same membrane. 
     
     
         19 . The integrated circuit according to  claim 8 , wherein the membrane comprises the magnetic film sandwiched between two passivation layers. 
     
     
         20 . A substrate supporting a thin, insulating, soft magnetic film of high magnetization, comprising:
 an amorphous substrate in which nitrided nanograins are immersed; and   a thin film formed from selectively oxidization of only the amorphous substrate.   
     
     
         21 . The substrate of  claim 20  wherein the nanograins comprise non-oxidized Fe-rich ferromagnetic nanograins forming a crystalline phase dispersed in an amorphous phase associated with the amorphous substrate. 
     
     
         22 . The substrate of  claim 20  further comprising a microstructure comprising a body-centered cubic crystalline phase of nitride nanograins. 
     
     
         23 . The substrate of  claim 20  further comprising a microstructure comprising a body-centered tetragonal crystalline phase of nitride nanograins. 
     
     
         24 . The substrate of  claim 20  wherein the thin film possesses soft magnetic properties defined by H c <10 Oe. 
     
     
         25 . The substrate of  claim 20  wherein the thin film has a nitride crystalline phase dispersed in an oxidized amorphous phase. 
     
     
         26 . The substrate of  claim 20  wherein the thin film elementally comprises Fe, N and O as well as an additional element X selected from the group consisting of: Al, Si, Ti, V, Cr, Mn, Cu and the lanthanides. 
     
     
         27 . The substrate of  claim 20  wherein the thin film elementally comprises Fe, N and O as well as an additional element X selected from the group consisting of: Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W, Ir, and Pt. 
     
     
         28 . The substrate of  claim 20  wherein the thin film forms a membrane for an integrated circuit. 
     
     
         29 . The substrate of  claim 28  wherein the membrane is fixed within the integrated circuit. 
     
     
         30 . The substrate of  claim 28  wherein the membrane is moveable within the integrated circuit. 
     
     
         31 . The substrate of  claim 28  wherein the membrane is formed as a wafer scale membrane covering an entire surface of the integrated circuit.