In some implementations, the substrate with the lower seed layer is lowered from a first temperature at which the lower seed layer is deposited, e.g., 300-500° C., to a lower second temperature, e.g., 20-300° C. The lower seed layer is exposed to the oxygen-containing gas or plasma at the lower second temperature. The second temperature can be at least 200° C. lower than the first temperature. For example, the second temperature can be room temperature, i.e., 20-22° C. The substrate is then raised to an elevated third temperature for deposition of the metal nitride of the superconductive layer.

In some implementations, the substrate with the lower seed layer is maintained at an elevated temperature, e.g., at or above 300° C., e.g., at the same temperature at which the lower seed layer is deposited, e.g., 400° C., and the substrate is exposed to the oxygen-containing gas or plasma at the elevated temperature.

In some implementations, the substrate with the lower seed layer is lowered from the first temperature to the second temperature, then raised up to elevated third temperature, e.g., at or above 300° C., e.g., 300-500° C., and the lower seed layer exposed to the oxygen-containing gas or plasma, at the elevated third temperature.

The exposure time can depend on pressure and temperature, and can be from 1 second to 120 minutes. For example, the exposure time for atmosphere at room temperature can be about 45 minutes. As another example, the exposure time for oxygen plasma with the substrate at the same temperature at which the lower seed layer is deposited, e.g., at about 400° C., can be about 30 seconds.