Surface contaminant reduction in controlled environments

A method, comprising:

• providing a substrate including an area of interest, wherein the substrate is disposed within an ultra-high vacuum (UHV) environment;
• positioning a mask in a first position over the area of interest, wherein the mask is held in the first position by a support bar;
• performing a first deposition of a reactive material from a reactive material source onto a first substrate region, wherein the mask, while in the first position, blocks deposition of the reactive material within the area of interest, and wherein the support bar blocks deposition of the reactive material within a second substrate region;
• positioning the mask in a second position over the area of interest, wherein the mask is held in the second position by the support bar, and wherein the mask, while in the second position, exposes the second substrate region;
• performing a second deposition of the reactive material from the reactive material source onto the second substrate region to circumscribe the area of interest with the reactive material;
• and
• capturing mobile surface molecules using the reactive material deposited onto the first substrate region and the second substrate region.

A method, comprising:

• providing a substrate including an area of interest disposed on a front surface of the substrate, wherein the substrate is disposed within a controlled environment;
• performing a deposition of a reactive material from a reactive material source onto a portion of the substrate, wherein the area of interest remains substantially free of the reactive material after deposition of the reactive material onto the portion of the substrate;
• and
• capturing mobile surface molecules using the reactive material deposited onto the portion of the substrate.