Quantitative Analysis Of Interface States Of Polymer Field Effect Transistor Based On Charge Pumping Method

The development of flexible electronics has greatly expanded the application fields of electronic devices,including medical devices,virtual reality,brain-computer interfaces,and more.Polymer transistors,due to their low cost and stretchable properties,have shown great potential in the development of flexible electronic devices.Donor-acceptor polymers can be used to manufacture stretchable electronic devices with stronger performance.In order to fully realize the advantages of polymer transistors in practical applications,it is necessary to conduct in-depth research and optimization of their performance.In organic field-effect transistors,the distribution of channel interface states is an important factor that affects the carrier transport and frequency response of the device.Previous studies on interface states in polymer transistors mostly relied on static or quasi-static techniques,and obtaining interface information under different frequency working conditions is important for the evaluation of polymer transistors,as the working frequency of logic devices is relatively high.To better understand the impact of carrier transport and interface state distribution in polymers on device performance,charge pumping is used to characterize the interface state distribution in polymer transistors.Charge pumping is a dynamic measurement method that can obtain changes in carrier concentration on the interface in a short time,and compared to other interface characterization methods,it provides a more intuitive understanding of carrier capture and emission processes.Firstly,the process flow and basic parameters for preparing DPPT-TT polymer transistors are introduced.DPPT-TT polymer transistors are prepared by solution spin-coating and electrode evaporation methods.Basic I-V tests are performed on the transistors to obtain output characteristic curves and transfer characteristic curves.The basic parameters of the transistors,including mobility,threshold voltage,and sub-threshold swing,are extracted by analyzing the transfer characteristic curves.Next,charge pumping is applied to PFETs to study the factors affecting charge pumping.The development process and basic principle of charge pumping are introduced.Due to the characteristics of three-terminal PFETs,a single-pulse charge pumping method is chosen to extract the interface state of the transistor.By studying the factors that affect the pump current waveform,the charge pumping process in PFET transistors is analyzed.Based on the pump current under different pulse amplitudes,the interface state distribution of the prepared PFET devices is extracted,ranging from 1×10¹³to 3×10¹³e V^-1cm^-2.Finally,charge pumping is used to study the interface state of different PFET devices,including the use of LB process to prepare semiconductor thin films and the effect of changing gate dielectric on the interface state of PFETs.The results show that the LB process can concentrate the distribution of interface state density,stabilize device performance,and optimize the distribution of interface states by mixing a small amount of PMMA in the semiconductor.PFETs were prepared using CYTOP and PS as gate dielectric materials,and the interface state density of CYTOP devices was between 6.4×10¹²and 9.2×10¹²e V^-1cm^-2,while the interface state density of PS devices was between 2.9×10¹²and 3.9×10¹²e V^-1cm^-2.In conclusion,the charge pumping method is applied to the investigation of various interfaces in this research in order to characterize the interfacial state distribution in polymer transistors.With a certain amount of theoretical and practical significance,this work offers fresh concepts and techniques for the improvement of polymer transistor performance and application.