Convertibility of conduction type in Al-N codoped ZnO thin films based on DC reactive magnetron sputtering

p-type conduction in ZnO thin films was realized by an Al-N codoping method. ZnO thin films were prepared in an NH/sub 3/-O/sub 2/ atmosphere with the substrate temperature in the range of 360-540/spl deg/C with a 20/spl deg/C space. Secondary ion mass spectroscopy (SIMS) tests proved that the presence of Al facilitated the incorporation of N into ZnO. A conversion from n-type conduction to p-type in a range of temperatures has been identified by measurements of the Hall effect and spreading resistance profiles. The Nls peak is located around 405.6eV in Al-N codoped ZnO thin films, compared with 401.7eV in the N alone-doped case, which may be due to the formation of Al-N bonds. The obtained p-type ZnO films shows a resistivity of 24.5 /spl Omega/cm, hole concentration of 7.48/spl times/10/sup 17/ cm/sup -3/ at room temperature. A model showing nitrogen incorporation suggests the possibility of realizing p-type ZnO films of low resistivity by optimizing thermal annealing.