Yu H, Zhang L, Li X H, Xu H Y, Liu Y C
J Nanosci Nanotechnol. 2016 Apr;16(4):3659-63. doi: 10.1166/jnn.2016.12340.
The amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) were demonstrated based on a double-layer channel structure, where the channel is composed of an ultrathin nitro-genated a-IGZO (a-IGZO:N) layer and an undoped a-IGZO layer. The double-layer channel device showed higher saturation mobility and lower threshold-voltage shift (5.74 cm2/Vs, 2.6 V) compared to its single-layer counterpart (0.17 cm2/Vs, 7.23 V). The improvement can be attributed to three aspects: (1) improved carrier transport properties of the channel by the a-IGZO:N layer with high carrier mobility and the a-IGZO layer with high carrier concentration, (2) reduced interfacial trap density between the active channel and the gate insulator, and (3) higher surface flatness of the double-layer channel. Our study reveals key insights into double-layer channel, involving selecting more suitable electrical property for back-channel layer and more suitable interface modification for active layer. Meanwhile, room temperature fabrication amorphous TFTs offer certain advantages on better flexibility and higher uniformity over a large area.
基于双层沟道结构展示了非晶铟镓锌氧化物（a-IGZO）薄膜晶体管（TFT），其中沟道由超薄的氮化a-IGZO（a-IGZO:N）层和未掺杂的a-IGZO层组成。与单层沟道器件（0.17 cm²/Vs，7.23 V）相比，双层沟道器件表现出更高的饱和迁移率和更低的阈值电压漂移（5.74 cm²/Vs，2.6 V）。这种改善可归因于三个方面：（1）具有高载流子迁移率的a-IGZO:N层和具有高载流子浓度的a-IGZO层改善了沟道的载流子传输特性；（2）降低了有源沟道与栅极绝缘体之间的界面陷阱密度；（3）双层沟道具有更高的表面平整度。我们的研究揭示了双层沟道的关键见解，包括为背沟道层选择更合适的电学性能以及为有源层选择更合适的界面修饰。同时，室温制备非晶TFT在更好的柔韧性和大面积更高的均匀性方面具有一定优势。
