Performance Investigation of Electrical Parameters of OTFT for Different Dielectric Materials

Abstract

Gate dielectrics have a significant impact on transistor performance. The selection of dielectric material is critical in the design of organic thin film transistor (OTFT). This study examines the effect of variation in dielectric material on the performance of OTFT with organic semiconductor layer of binaphth[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) using ATLAS simulation. Electrical features including maximum drain current (I_dmax), Current on-off ratio (I_on/I_off),threshold voltage (V_th), and transconductance(g_max) differ drastically depending on the dielectric material. The change in electrical parameters is mostly caused by the gate insulating capacitance of the dielectric layer. Using variety of gate insulators, including SiO₂, HfO₂, Al₂O₃ and Si₃N₄, 2D numerical simulations of OTFT are performed. Study confirms that high current on-off ratio (I_on/I_off) with HfO₂ dielectric makes it suitable for various fast switching applications. Organic transistors have a promising future with memory devices, inverters, DNA sensors and RFID tags among its many possibilities.