Provided are an n-type carbon nanotube field effect transistor (CNT FET) and a method of fabricating the n-type CNT FET. The n-type CNT FET may include a substrate; electrodes formed on the substrate and separated from each other; a CNT forrmed on the substrate and electrically connected to the electrodes; a gate oxide layer formed on the CNT; and a gate electrode formed on the gate oxide layer, wherein the gate oxide layer contains electron donor atoms which donate electrons to the CNT such that the CNT may be n-doped by the electron donor atoms.