Vertical Structure TFT Using Thin Gate Dielectric

Abstract

Oxide thin film transistor (TFT) is widely used for a display backplane. It can also be used in many applications, such as sensors and wearable devices that require low power consumption. The channel of the existing TFT is formed horizontally, but the structure in this study is formed vertically, so it is more resistant to stretching. For low power consumption, the driving voltage must be lowered. To achieve the goals above, vertical structure TFT is being studied by several groups. In this study, a vertical structure TFT using a thin gate dielectric film was developed. Figure 1 shows the structure of the vertical TFT. As shown in Fig. 1, IGZO was used as an active layer and deposited by RF magnetron sputter. The dielectric between the source/drain and gate was deposited by ALD (Atomic Layer Deposition). Since the channel length is determined by the thickness of the gate electrode, short channel length TFT is formed easily for low driving voltages. In addition, a thin gate dielectric was used to decrease the threshold voltages of the TFT. Since a very thin gate dielectric was used, a low threshold voltage was obtained, which enable low power consumption TFT circuits. Figure 1