Microelectronic devices with through-silicon vias and associated methods of manufacturing such devices. One embodiment of a method for forming tungsten through-silicon vias comprising forming an opening having a sidewall such that the opening extends through at least a portion of a substrate on which microelectronic structures have been formed. The method can further include lining the sidewall with a dielectric material, depositing tungsten on the dielectric material such that a cavity extends through at least a portion of the tungsten, and filling the cavity with a polysilicon material.