Methods and systems for manufacturing superconductor devices
The various embodiments described herein include methods for manufacturing superconductor devices. In some embodiments, a method of manufacturing a superconductor includes: (1) manufacturing a first superconductor device; (2) characterizing the first superconductor device, including: (a) obtaining x-ray diffraction spectra of the first superconductor device; and (b) identifying a ratio of a first cubic phase peak to a second cubic phase peak in the x-ray diffraction spectra; (3) adjusting a manufacturing parameter based on the identified ratio; and (4) manufacturing a second superconductor device with the adjusted manufacturing parameter.
1. A method of manufacturing a superconductor, comprising:
manufacturing a first superconductor device;
characterizing the first superconductor device, including:
obtaining x-ray diffraction spectra of the first superconductor device; and
identifying a ratio of a first cubic phase peak to a second cubic phase peak in the x-ray diffraction spectra;
obtaining a second ratio corresponding to a second superconductor device;
adjusting a manufacturing parameter based on the identified ratio and the second ratio, wherein the manufacturing parameter corresponds to one or more of: a voltage source, a duty cycle, a pressure, and a plasma mixture; and
manufacturing a third superconductor device with the adjusted manufacturing parameter.
2. The method of claim 1 , wherein manufacturing the first superconductor device comprises:
obtaining a substrate composed of silicon;
depositing a first layer on the substrate, the first layer composed of silicon and nitrogen; and
depositing a superconductor layer on the first layer, the superconductor layer composed of niobium nitride.
3. The method of claim 2 , wherein the superconductor layer is deposited via a physical vapor deposition (PVD) process.
4. The method of claim 3 , wherein the superconductor layer is deposited via an argon and nitrogen plasma.
5. The method of claim 4 , wherein the manufacturing parameter is a percentage of nitrogen in the argon and nitrogen plasma.
6. The method of claim 4 , further comprising maintaining the argon and nitrogen plasma at a pressure in the range of 12 milliTorr (mT) to 20 mT during the PVD process.
7. The method of claim 2 , wherein depositing the superconductor layer on the first layer comprises transferring niobium from a niobium sputter target to the superconductor layer.
8. The method of claim 7 , further comprising supplying a voltage to the niobium sputter target via a voltage source, wherein the voltage source is configured to utilize 2 kiloWatts (kW) to 4 kW of power.
9. The method of claim 8 , wherein the voltage source comprises a pulsed direct current (DC) voltage source.
10. The method of claim 9 , wherein the pulsed DC voltage source has a duty cycle in the range of 40% and 70%.
11. The method of claim 2 , further comprising maintaining the substrate at a temperature in the range of 300 degrees Celsius (° C.) to 400° C. during deposition of the superconductor layer.
12. The method of claim 2 , wherein the first layer is deposited via a chemical vapor deposition (CVD) process.
13. The method of claim 1 , wherein the first cubic phase peak corresponds to a (111) lattice structure of niobium nitride (NbN) within the superconductor device; and
wherein the second cubic phase peak corresponds to a (200) lattice structure of the NbN.
14. The method of claim 13 , wherein characterizing the first superconductor device further comprises determining whether the x-ray diffraction spectra includes a superlattice phase peak for the NbN; and
wherein, in accordance with a determination that the x-ray diffraction spectra includes the superlattice phase peak, the third superconductor device is manufactured with a superconductor layer having a thickness less than 40 nm.
15. The method of claim 1 , wherein the first superconductor device comprises a superconductor layer with a thickness greater than 40 nm;
wherein characterizing the first superconductor device further comprises determining whether the identified ratio is greater than a preset threshold; and
wherein:
in accordance with a determination that the identified ratio is greater than the preset threshold, the third superconductor device is manufactured with a superconductor layer having a thickness less than 40 nm; and
in accordance with a determination that the identified ratio is less than the preset threshold, the third superconductor device is manufactured with a superconductor layer having a thickness greater than 40 nm.
16. The method of claim 15 , wherein manufacturing the third superconductor device includes depositing a protective layer over the superconductor layer, wherein the protective layer is composed of aluminum nitride.
17. The method of claim 16 , wherein manufacturing the third superconductor device further comprises, after depositing the protective layer, annealing the third superconductor device.