A three-dimensional (3D) memory and a method for manufacturing the same are disclosed. According to one embodiment, the 3D memory comprises a thin-film transistor. The thin-film transistor has a source region and a drain region disposed separately. The source region comprises a first source region and a second source region disposed between the first source region and the drain region. The first source region is p-type of doping, the second source region is n-type of doping, and the drain region is n-type of doping.