Growth of boron-doped ZnO thin films by atomic layer deposition

ZnO films have been grown by atomic layer deposition (ALD) using diethylzinc (DEZn) and H 2O as reactant gases. The diborane (B 2H 6) gas has also been successfully used as an n-type dopant gas to obtain low-resistivity ZnO films. A high electron mobility of about 30 cm 2/V s was obtained for undoped ZnO films of 220 nm thick, and a low resistivity of 6.4×10 −4 Ω cm was achieved for B-doped ZnO films of only 200 nm thick. It was found that the electrical properties of ZnO films strongly depend on the injected amount of B 2H 6 during the deposition and on the injection timing of B 2H 6 relating to DEZn and H 2O.