Point-of-use enrichment of gas mixtures for semiconductor structure fabrication, and systems for providing point-of-use enrichment of gas mixtures, are described herein. In an example, a system for fabricating a semiconductor structure includes a process chamber for processing a substrate of a semiconductor structure. A gas supply is coupled to the process chamber. A point-of-use gas enrichment module is coupled to the gas supply. The point-of-use gas enrichment module is configured to concentrate a first gas composition to provide a second gas composition to the gas supply for the process chamber. The second gas composition has a relative amount of a hydride species greater than a relative amount of corresponding hydride species in the first gas composition.