Scaling limits and MHz operation in thiophene‐based field‐effect transistors

Abstract

To achieve high performance organic field effect transistors (OFETs) with enhanced currents, high switching speeds and improved integration density the channel length L is downscaled to the sub‐micrometer regime. The influence of important scaling parameters on the electrical performance of bottom contact devices is analyzed. High‐mobility oligo‐ and polythiophenes were used as semiconductor, which combine the advantages of highly ordered growth with processibility from solution. Devices with optimized parameters exhibit high switching frequencies beyond 2 MHz. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Patterned electrode vertical field effect transistor: Theory and experiment

“…at least 1.5 times the length of h D (i.e., h D :L ratio of 1:1.5) and, in some cases, 5 times as much. 34,35 The scaling in the case of the vertical transistor configuration is rather associated with the "tunnel" effect discussed earlier. If the "tunnel" effect is the dominant one for this scaling of the dielectric thickness then the ratio to be kept is that of h D :D. Transfer characteristics presented in Fig.…”

Self‐Aligned Megahertz Organic Transistors Solution‐Processed on Plastic

“…In the context of the reported literature these represent state-of-the-art values for solution-processed organic devices fabricated on plastic foil. [12][13][14][15][16][17][18][19][20][21] This is achieved without the need for a rigid substrate, using solution-processed dielectric and semiconductor, and is regardless of the relatively low effective mobility of these devices ( µ sat = 0.03-0.06 cm 2 V −1 s −1 ), highlighting the impact and importance of self-aligned, low stray capacitance architecture on device performance.…”

“…Only a handful of reports on OFET alternating current (AC) characterization use fabrication techniques that even partially fulfi l the requirements set out above. [12][13][14][15][16][17][18][19][20][21][22][23] However to build functional fl exible circuits it is important to understand how to reconcile device fabrication and performance. [24][25][26] This is a requirement if plastic electronics are to be implemented in applications such as radio frequency identifi cation (RFID) tags which operate at megahertz frequencies.…”

“…While much of the reported literature on OFETs focuses on the static behavior and figures of merit such as field‐effect mobility, very little explores the frequency response of devices. Only a handful of reports on OFET alternating current (AC) characterization use fabrication techniques that even partially fulfil the requirements set out above . However to build functional flexible circuits it is important to understand how to reconcile device fabrication and performance .…”

Soft Nanolithography by Polymer Fibers

“…= {{W}\over{{2L}}}C\mu \left( {V_{G_S} - V_{TH} } \right)^2$ , where C is the gate dielectric capacitance per unit area, are used to estimate the charge carrier mobility in microgap devices in the linear and saturation regime, respectively. In contrast, a model for the linear and saturation regime of short‐channel transistors is found to extend the gradual channel approximation model by introducing ohmic contact resistances in series at source ( R S ) and drain ( R D ), as follows:26 …”