Film resistor with a constant temperature coefficient and production of a film resistor of this type
View Patent ↗The invention relates to a film resistor ( 1 ) comprising a carbon-containing material ( 3 ) into which clusters ( 4 ) of conductive cluster material are introduced, wherein the conductive cluster material has a positive temperature coefficient. The clusters ( 4 ) are surrounded by a graphite casing and embedded in the carbon-containing material ( 3 ). Furthermore, the cluster material is present in a thermodynamically stable phase. The invention also relates to a method for producing a film resistor ( 1 ), wherein a PVD process is carried out on a carrier substrate ( 11 ) using a sputtering material under a reactive atmosphere of a carbon-containing gas, and therefore the carbon-containing gas is dissociated and a carbon-containing layer ( 3 ) is deposited on the carrier substrate ( 11 ), with clusters ( 4 ) of the sputtering material being embedded in said carbon-containing layer, wherein the carbon-containing layer ( 3 ) is heated to a predetermined temperature while the PVD process is carried out, with the sputtering material or a compound of the sputtering material forming in a stable phase at said temperature.
1. A film resistor ( 1 ) comprising a carbon-containing material ( 3 ) into which clusters ( 4 ) of conductive cluster material are introduced,
wherein the conductive cluster material has a positive temperature coefficient;
wherein the clusters ( 4 ) are surrounded by a graphite shell and are embedded in the carbon-containing material ( 3 ),
characterized in that
the cluster material is present in a thermodynamically stable phase.
2. The film resistor ( 1 ) according to claim 1 , wherein the proportion of cluster material is selected below the percolation threshold for the cluster material so that total percolation of the clusters in the carbon-containing material does not occur.
3. The film resistor ( 1 ) according to claim 1 ,
wherein the carbon-containing material exhibits a matrix with amorphous carbon or amorphous hydrocarbon.
4. The film resistor ( 1 ) according to claims 1 , wherein the cluster material contains metal or a metal alloy, in particular nickel, a nickel alloy, copper, a copper alloy, iron, or an iron alloy, cobalt, or a cobalt alloy.
5. The film resistor ( 1 ) according to claims 1 , wherein the proportion of cluster material in the carbon-containing film is adjusted in such a way that the temperature coefficient of the film resistor ( 1 ) is zero.
6. A method for selecting a conductive cluster material for clusters ( 4 ) during the production of a film resistor ( 1 ) according to claim 1 , in that the clusters ( 4 ) are formed by deposition in a PVD process under a reactive atmosphere using a carbon-containing gas, wherein the cluster material is selected based on a predetermined desired temperature coefficient of resistance, in particular a desired temperature coefficient of resistance equal to or greater than zero, so that the proportion of cluster material, at which the desired temperature coefficient is obtained, is below the percolation threshold.
7. The method according to claim 6 , wherein the cluster material that is chosen is a material that is chemically inert to air, water, or oil.
8. The method according to claim 6 , wherein the cluster material that is chosen is a material with which there is essentially no diffusion motion of the clusters ( 4 ) and/or the cluster material in the carbon-containing material.
9. The method for producing a film resistor ( 1 ), wherein a PVD process is carried out with a sputtering material on a carrier substrate ( 11 ) under a reactive atmosphere of a carbon-containing gas, so that the carbon-containing gas is disassociated, and a carbon-containing film ( 3 ), in which clusters ( 4 ) of the sputtering material are embedded, is deposited on the carrier substrate ( 11 ),
wherein, while the PVD process is carried out, the carbon-containing film ( 3 ) is heated to a predetermined temperature at which the sputtering material or a compound of the sputtering material is produced in a stable phase.
10. The method according to claim 9 , wherein during the PVD process the carrier substrate is heated to a temperature below 600° C., in particular, to a temperature between 150° C. and 300° C.
11. The method according to claim 9 , wherein the carbon-containing gas has ethane, ethylene, ethene, or ethyne.
12. The method according to claims 9 , wherein the concentration of the carbon-containing gas determines the proportion of sputtering material in the carbon-containing film ( 3 ), with the concentration of the carbon-containing gas being adjusted in such a way that the clusters ( 4 ) of sputtering material in the carbon-containing film ( 3 ) are separated from each other by the graphene films.
13. The method according to claim 12 , wherein the proportion of sputtering material is selected in such a way that a predetermined temperature coefficient of resistance for the film resistor ( 1 ) is obtained.
14. Use of the film resistor according to claim 4 as the sensor layer, wherein a strain-sensitive area is formed by the film resistor ( 1 ).
15. A film resistor that can be produced by a method according to claims 9 .