Some embodiments include a semiconductor device having a stack structure including a plurality of alternating tiers of dielectric material and poly-silicon formed on a substrate. Such a semiconductor device may further include at least one opening having a high aspect ratio and extending into the stack structure to a level adjacent the substrate, a first poly-silicon channel formed in a lower portion of the opening adjacent the substrate, a second poly-silicon channel formed in an upper portion of the opening, and WSiX material disposed between the first poly-silicon channel and the second poly-silicon channel in the opening. The WSiX material is adjacent to the substrate, and can be used as an etch-landing layer and a conductive contact to contact both the first poly-silicon channel and the second poly-silicon channel in the opening. Other embodiments include methods of making semiconductor devices.