发光学报, 2015, 36 (11): 1320, 网络出版: 2015-11-30
负电荷层对a-IGZO TFT阈值电压的影响
Effects of Negative Charge Layer on The Threshold Voltage of a-IGZO TFT
a-IGZO薄膜晶体管 磁控溅射法 负电荷层 平带电势 阈值电压 a-IGZO TFT MS sputtering negative charge layer flat band potential threshold voltage
摘要
采用脉冲直流磁控溅射的方式沉积In-Ga-Zn-O (IGZO)膜层作为TFT的有源层。在TFT沟道处的有源层和绝缘层的界面上,通过溅射法制作一定厚度的负电荷层对阈值电压(Vth)进行调制,使得Vth由-3.8 V升高至-0.3 V,器件由耗尽型向增强型转变。通过增加Al2O3作为负电荷层,可有效地将Vth控制在0 V附近,并且提高其器件稳定性,得到较好的电学特性: 电流开关比Ion/Ioff>109,亚阈值摆幅SS为0.2 V/dec,阈值电压Vth为-0.3 V,迁移率μ为9.2 cm2 /(V·s)。
Abstract
TFT device with In-Ga-Zn-O (IGZO) film as the active layer deposited by pulse DC sputtering was fabricated. An Al2O3 film which was also deposited by sputtering was sandwiched between the active layer and an insulating layer. The Al2O3 acted as a negative charge layer for threshold voltage modulation (Vth). It raised the Vth from -3.8 V to -0.3 V,enhancing the formation of a depletion mode device. The application of Al2O3 as a negative layer can effectively control Vth around 0 V and enhance the stability of the device. Improved device characteristics such as: on/off current ratio (Ion/Ioff)>109,sub-threshold slope(SS) of 0.2 V/dec,Vth of -0.3 V,and mobility (μ) of 9.2 cm2/(V·s) were therefore achieved.
丁磊, 张方辉. 负电荷层对a-IGZO TFT阈值电压的影响[J]. 发光学报, 2015, 36(11): 1320. DING Lei, ZHANG Fang-hui. Effects of Negative Charge Layer on The Threshold Voltage of a-IGZO TFT[J]. Chinese Journal of Luminescence, 2015, 36(11): 1320.