A method for manufacturing a semiconductor feature includes: alternatingly forming first and second dielectric layers on a semiconductor substrate along a vertical direction; forming multiple spaced-apart trenches penetrating the first and second dielectric layers; forming multiple support segments filling the trenches; removing the second dielectric layers to form multiple spaces; forming multiple conductive layers filling the spaces; removing the support segments to expose the conductive layers and the first dielectric layers; selectively forming a blocking layer covering the first dielectric layers outside of the conductive layers; forming multiple selectively-deposited sub-layers on the exposed conductive layers outside of the blocking layer and each connected to one of the conductive layers; forming multiple channel sub-layers on the selectively-deposited sub-layers outside of the blocking layer; removing the blocking layer; forming multiple isolation sub-layers filling the trenches; and forming multiple source/drain segments each connected to corresponding ones of the channel sub-layers.