Performance of ZnO TFTs with AlN as Insulator

摘要

The performance of ZnO TFTs fabricated via RF sputtering at room temperature, with Aluminium Nitride (AlN) as the underlying insulator are reported for the first time. The resulting mobility of the device is significantly improved, in comparison to that of SiN insulator, with corresponding values of 3.0 cm~2/Vs for AlN and 0.2-0.7 cm~2/Vs for SiN cm~2/Vs respectively. The AlN devices show a higher instability with respect to gate bias stress, despite the fact that the interface states are reduced due to an improved lattice match with ZnO. A possible cause is the interaction of ultra-fast interface states with bulk traps in the ZnO, which are also well known to contribute to excess background electron concentration in the material.