Temperature Dependence of Carbon Nanotube Field Effect Transistor under Non-ballistic conduction considering Different Dielectric Materials Safayat-Al Imam 1 , Nasheen Kalam 2 , Sharmin Abdhullah 3 1-3 Department of EEE, Ahsanullah University of Science and Technology, Dhaka, 1208, Bangladesh Abstract This paper deals with a simulation model to analyse the behaviour of carbon nanotube field effect transistors (CNTFETs) under non-ballistic conditions and based on the changes of gate dielectric constant the performance of CNT- FETs has been explored in detail as a function of temperature. A thorough study of the combined non-ballistic effect on the performance of CNTFETs has been conducted with different principle characteristics of CNTFETs and the output of the device has been analysed. Effects on the drain current under different temperature with different dielectric constant is ob- served under different gate voltages Also it has been observed that within a certain range of temperature both on-state and off-state current retains in steady state. However with a higher value of temperature and dielectric constants, on and off state current changes and as a result it degrades the current ratio. In addition, the ratio of quantum to insulator capacitance, drain-induced barrier lowering (DIBL) with respect to the changes of gate dielectric constant as a function of temperature are further investigated. Quantum capacitance increased with temperature which increases the ratio of quantum to insulator capacitance. The DIBL vary slightly with higher value dielectric material and reaches to desired ballistic condition value with an ambient temperature. Keywords on-state current, off-state current, drain-induced barrier lowering (DIBL), Quantum Capacitance. 1. Introduction One of the most imaging features of carbon nanotube is its application on electronics field especially in Carbon nano- tube field effect transistor (CNTFET). The motivation of research in CNFET is fuelled by the unique quasi-ideal electronic as well as optical characteristics of carbon nano- tube [1],[2].Just like MOSFET it supplies electrons from source terminal to drain terminal for collection. However, properties like higher on-state current, high channel density and high electric density makes a CNTFET superior than MOSFET [3]-[6]. The scaling of MOSFET's increases with the number of transistors integrated on a chip. Due to MOS scaling, capacitance of the device increased while decreasing the thickness of the oxide layer. In case of CNTFET, gate oxide thickness maintains an inverse relationship with drain current [7].An insulator with higher dielectric constant can be the answer. For modelling a CNTFET, mesoscopic physics analysis with higher dielectric constant gives dif- ferent aspects of CNTFET and their structures. Also like MOSFET, temperature will play a vital role in the CNTFET performance and characteristics [9]. Hence, various proper- ties of CNTFET is investigate under different temperatures. When channel length of CNT transistor has a length smaller than the carrier mean free path (MPF) but larger than the Coulomb blockade length, it shows the ballistic nature. Due to the variance of energy domain, non-ballistic transport in CNTs becomes prominent [10].As a result, the mobility of the carrier changes due to the fluctuation of the transmis- sion coefficient of carrier to travel through a single-defect coulomb potential channel. However, contamination, va- cancies, contact to the substrate and absorbed molecules can also cause the non-ideal behaviour in the CNT channel. The non-ballistic transport in CNTs is likely to attract more re- search attention in the near future. Elastic scattering mecha- nism in the CNT channel region conducts a reduced potential drop in the region. Channel resistance due to the elastic scattering increases which effects the drain current. Also change in band gap due to the strain effect on CNT and tunnel current causes the non-ballistic conditions over the CNTFET. In this paper, only the combined effects of these non-ideal approaches are considered. Also the effects of varying temperature are investigated in terms of on-state