材料期刊网

采用射频磁控溅射法，在热氧化 p 型硅基片上制备了双沟道层非晶氧化铟锌(a-IZO)和氮掺杂氧化铟锌(a-IZON)薄膜晶体管(TFTs)，并研究了双沟道层对器件电学性能和温度稳定性的影响。研究发现， a-IZO/IZON双沟道层TFTs具有较高的场效应迁移率，为23.26 cm2/(V×s)，并且其阈值电压相较于单层a-IZO-TFTs正向偏移。这是由于氮掺杂可以减少沟道层中的氧空位，抑制载流子浓度，使器件具有更好的阈值电压。而a-IZO层避免了由于氮掺杂导致的场效应迁移率和开态电流的下降，提升了器件的电流开关比。从298 K至423 K的器件转移特性曲线中发现，双沟道层器件相较于单沟道层器件的温度稳定性更佳，这可归因于a-IZON层的保护作用。氮掺杂可以减少氧在背沟道层表面的吸收/解吸反应，改善器件的稳定性。

The nitrogen-doped amorphous indium-zinc-oxide thin film transistors with double channel layers (a-IZO/IZON-TFTs) were fabricated by RF magnetron sputtering of IZO target on the thermal oxidized p-type Si substrate. Influence of the double channel layers on the electrical performance and thermal stability of the devices were investigated. It is found that a-IZO/IZON-TFTs have high field effect mobility of 23.26 cm2/(V×s) and more positively shifted threshold voltage than that of a-IZO-TFTs. This is ascribed to the doped nitrogen which can help reduce oxygen vacancy in the channel layer, suppress carrier concentration and make the devices have a better threshold voltage. Meanwhile, employing a-IZO thin film can avoid the sharp drop of field effect mobility and drain on current caused by nitrogen doping on a-IZON layer, leading to promotingIon/Iof ratio effectively. Besides, ac-cording to the transfer characteristics measured at temperatures from 298 K to 423 K, devices with a-IZO/IZON double layers have superior performance and thermal stability to TFTs of single channel layer, which can be as-cribed to the protective effect of a-IZON thin film on the channel layers. The doped nitrogen can reduce the adsorp-tion/desorption reaction of oxygen molecules on the back channel layer, leading to a significant improvement on thermal stability of the devices.