The present invention provides improved semiconductor wafer structures having isotopically-enriched layers and methods of making the same. The housing includes a valve assembly movable in response to air pressure provided to selected ports in the housing. Hammers are pivotally supported by the chassis, for each being pivotally moved in accordance with depression of the associated key. Various patching policies can be instituted. Each device portal is configured to provide accurate and controlled delivery of the device to the target area.