为降低氧化锌薄膜晶体管(ZnO-TFT)的关态电流(Ioff),提高开关电流比(Ion/Ioff),采用磁控溅射法制备掺硅氧化锌薄膜晶体管(SZO-TFT)和SZO/ZnO双层有源层结构的TFT器件,研究了Si含量对SZO薄膜透光性和SZO-TFT电性能的影响,比较了单层与双层有源层结构TFT器件的电特性。与ZnO-TFT相比,SZO-TFT的Ioff低2个数量级,最低达1.5×10-12 A; Ion/Ioff高两个数量级,最高达7.97×106。而SZO/ZnO双有源层结构的TFT器件可在不降低载流子迁移率的情况下, Ion/Ioff比ZnO-TFT提高近两个数量级,有效改善了器件的整体性能。

In order to reduce the off-state leakage current and increase the on/off current ratio in ZnO thin-film transistor (ZnO-TFT), Si-doped ZnO thin-film transistors (SZO-TFTs) and TFT with SZO/ZnO acted as dual-active-layer were fabricated by magnetron sputtering method. Effects of silicon concentration on optical transmittance of Si-doped ZnO thin film and electrical properties of SZO-TFT were investigated. Moreover, the electrical characteristics of the TFT with SZO/ZnO acted as dual-active-layer were compared with those of the TFTs with ZnO and Si-doped ZnO acted as single-active-layer. The experimental results indicated that, compared with undoped ZnO-TFT, the off-state leakage current of SZO-TFT reduces by more than two orders of magnitude, down to 1.5×10-12 A, and the on/off current ratio increases by more than two orders of magnitude with a maximum value up to 7.97×106; The SZO/ZnO dual-active-layer architecture used in the ZnO-based TFT could increase the on/off current ratio by about two orders of magnitude with no reduction in carrier mobility, and thus optimize the performance of the ZnO-based TFT.