During the last years, a large number of publications related with oxide based TFTs have appeared. Polycrystalline binary oxides, like ZnO or SnO₂, or more recently multicomponent amorphous oxides, like IZO or GIZO, have been the semiconductors responsible for the excellent performance of these TFTs. However, little attention has been given to the dielectric layer development, being most of the TFTs based on “standard” dielectrics, like thermal SiO₂ or PECVD SiN_x. In this work several high-k gate dielectrics produced without intentional heating by r.f. magnetron sputtering are explored and used to produce TFTs based on GIZO semiconductor. Binary oxides, like Ta₂O₅ and HfO₂, lead to good performing devices: for example, with Ta₂O₅ high field-effect mobility (µ_FE) and low threshold voltage (V_T) are obtained, ≈40 cm²/Vs and ≈1 V respectively, at the cost of an undesirably high gate leakage current (I_G), that can reach 1 µA at V_D=V_G=15 V, even when 300 nm thick dielectrics are used. The high I_G should be related with a non-favorable band offset between GIZO and Ta₂O₅ (or HfO₂) and dielectric crystallization (mainly HfO₂). In order to decrease I_G, mixtures of the binary oxides referred above with amorphous and high bandgap dielectrics, like SiO₂ or Al₂O₃, are produced by co-sputtering. The TFTs based on these multicomponent dielectrics still present high µ_FE and low V_T: values like 15-30 cm²/Vs and 1.5-3.0 V, respectively, are obtained depending on the composition of the multicomponent dielectric, which is controlled by the r.f. power applied to the SiO₂ or Al₂O₃ target. However, I_G decreases considerably, being now possible to obtain values as low as 1 pA at V_D=V_G=15 V. Top and bottom-gate structures are analyzed, but generally the former leads to worse properties, which is mainly ascribed to the high bombardment at which the GIZO surface (hence, the GIZO/dielectric interface) is exposed during the dielectric deposition in top-gate structures.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/16035 must be provided.

1. Nanomaterials for better life
2.  Blue and Yellow Light Emitting Diodes using IZO as anode
3. Co-sputtered dielectrics for transparent electronics
4. 3D position sensitive detectors for pattern recognition applications