| 摘要 |
As part of the fabrication of a magnetic tunnel junction (MTJ), a magnesium oxide (MgO) tunnel barrier is reactively sputter deposited from a Mg target in the presence of reactive oxygen gas (O<SUB>2</SUB>) in the "high-voltage" state to assure that deposition occurs with the Mg target in its metallic mode, i.e., no or minimal oxidation. Because the metallic mode of the Mg target has a finite lifetime, a set of O<SUB>2 </SUB>flow rates and associated sputter deposition times are established, with each flow rate and deposition time assuring that deposition occurs with the Mg target in the metallic mode and resulting in a known tunnel barrier thickness. The commencement of undesirable Mg target oxidation is associated with a decrease in target voltage, so the sputtering can also be terminated by monitoring the target voltage and terminating application of power to the target when the voltage reaches a predetermined value.
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