Effects of thermal annealing and gamma irradiation on HfO < inf > 2 < /inf > thin films deposited on GaAs

Abstract

Si-based Metal-Oxide-Semiconductor (MOS) devices have played acritical role in Complementary Metal Oxide Semiconductor (CMOS) device technology. The down scaling of the size of these devices have been the preferred route to improve the device performance. This results in high OFF state leakage current due to quantum tunneling. In this connection, keeping the future technology advancement in mind, there is a need for an alternative gate dielectric (like HfO2) material as well as superior semiconductor substrates (like GaAs). Here, we have deposited HfO2 thin films on GaAs by using RF-Magnetron Sputtering Technique. Rutherford Backscattering Spectrometry (RBS), X-Ray Reflectivity (XRR), and Energy-Dispersive X-ray analysis (EDX) measurements were performed on these films. Monoclinic phase of HfO2 films and a considerable increase in the leakage current are observed for annealing temperature above 300°C. Furthermore, a set of samples were subjected to gamma irradiation. The increase in leakage current with respect to irradiation dose has been observed, which shows the existence of several types of defects in oxide films.