Heavily doped n-type a-IGZO by F plasma treatment and its thermal stability up to 600 °C

We report the electrical properties and thermal stability of heavily doped, amorphous indium-gallium-zinc-oxide (a-IGZO) treated with fluorine (F) plasma. When the F doping concentration in a-IGZO is 17.51 x 10(21)/cm(-3), the a-IGZO exhibits a carrier concentration of 6 x 10(19) cm(-3), a resistivity of 3 x 10(-3) Omega cm, and a Hall mobility of 20 cm(2)/V s. This indicates that F is a suitable n-type dopant in a-IGZO. The similarity of the ionic radius of F to that of oxygen (O) allows substitutional doping by replacing O with F or the occupation of the oxygen vacancy (V-O) site by F and consequent reduction in defect density. The semiconducting property of a-IGZO can change into metallic behavior by F doping. The defect passivation by F incorporation is confirmed by the XPS depth profile, which reveals the significant reduction in the V-O concentration due to the formation of In-F bonds. The heavily doped a-IGZO exhibits thermally stable conductivity up to 600 degrees C annealing and thus can be widely used for the ohmic contact of a-IGZO devices. Published by AIP Publishing.