(The) properties of high mobility oxide TFT with indium-tin-zinc oxide active layer deposited by using electron cyclotron resonance sputtering method

Abstract

Recently, oxide semiconductors have been adopted as an active layer in thin-film transistors (TFTs). Especially, In-Ga-Zn-O semiconductors have been researched intensively, because of their high mobility with uniformity. However, alternative oxide semiconductors with much high mobility is required to be applied in high resolution displays. Furthermore, retaining a device stability under various condition, such as temperature and bias stress, is a critical issue for this high mobility oxide semiconductors. To solve this issues, we tried to enhance the stability of oxide TFTs by depositing a densified In-Sn-Zn-O (ITZO) film which has higher mobility than that of IGZO film. Since an electron cyclotron resonance (ECR) sputter utilizes the ECR plasma which is generated in low pressure and has highly dense plasma, thin-films with high density can be deposited, and we focused on to this method. In this paper, we applied the ECR sputtering method on the deposition of ITZO films, and analyzed their film properties. Furthermore, the ECR ITZO film is used as the active layer in TFTs. Using these TFTs, the electrical properties have been investigated, and the device stability under a various bias-temperature stress was analyzed.