Extraction of contact resistance and channel parameters from the electrical characteristics of a single bottom-gate/top-contact organic transistor

Takagaki, Shunsuke; Yamada, Hirofumi; Noda, Kei

doi:10.7567/jjap.55.03dc07

Cited by 9 publications

(9 citation statements)

References 30 publications

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“…Various solutions for improving the accuracy in the evaluation of R C from I – V curves have been proposed . Xu et al created a modified gated transfer length model (M‐TLM) that takes advantage of the fact that the slope of the linear fit is less sensitive to variations in data than the intercept .…”

Section: Characterizing Contact Resistance In Ofetsmentioning

confidence: 99%

Contact Resistance in Organic Field‐Effect Transistors: Conquering the Barrier

Waldrip

Jurchescu

Gundlach

et al. 2019

Adv Funct Materials

241

261

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Organic semiconductors have sparked interest as flexible, solution processable, and chemically tunable electronic materials. Improvements in charge carrier mobility put organic semiconductors in a competitive position for incorporation in a variety of (opto-)electronic applications. One example is the organic field-effect transistor (OFET), which is the fundamental building block of many applications based on organic semiconductors. While the semiconductor performance improvements opened up the possibilities for applying organic materials as active components in fast switching electrical devices, the ability to make good electrical contact hinders further development of deployable electronics. Additionally, inefficient contacts represent serious bottlenecks in identifying new electronic materials by inhibiting access to their intrinsic properties or providing misleading information. Recent work focused on the relationships of contact resistance with device architecture, applied voltage, metal and dielectric interfaces, has led to a steady reduction in contact resistance in OFETs. While impressive progress was made, contact resistance is still above the limits necessary to drive devices at the speed required for many active electronic components. Here, the origins of contact resistance and recent improvement in organic transistors are presented, with emphasis on the electric field and geometric considerations of charge injection in OFETs.semiconductors with superior intrinsic charge transport properties, there is a stringent need to improve the device properties in order to allow organic devices to fulfill their technological prospectives. In the organic semiconductor community, contact resistance (R C ) has come under increased scrutiny as it is apparent that the final device performance is often domi nated by carrier injection, rather than the transport through the semiconductor layer. Contact resistance can impact OFET development in multiple ways. First, if not accounted for, a high contact resistance may lead to inaccurate extraction of the device parameters. Second, any inaccuracies in parameter extraction can have significant consequences on material development, from generating incorrect structure-property relationships to discarding organic semiconductors whose efficient intrinsic electrical properties have been masked by inefficient contacts. Beyond OFET and semiconductor characterization, analog, low power, and high frequency applications require a greater level of device parameter control than has been obtained in typical DC, high-voltage OFETs. For analog applications, e.g., integration of conditioning circuits such as local sense amps for distributed flexible sensor arrays, nonlinearity of the transistor response inhibits proper functioning and limits applicability of common models used to design circuitry. Low power device development for novel materials are hindered by the high voltage turn-on and current suppression in devices with large R C . Considering high-frequency applications, Klauk suggest...

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Section: Characterizing Contact Resistance In Ofetsmentioning

confidence: 99%

Contact Resistance in Organic Field‐Effect Transistors: Conquering the Barrier

Waldrip

Jurchescu

Gundlach

et al. 2019

Adv Funct Materials

241

261

View full text Add to dashboard Cite

show abstract

“…The two steps combine the benefits and overcome the drawbacks of the two classes of established extraction approaches, namely 'single transistor methods' and 'channel-length-scaling approaches'. [10] 'Single transistor methods' seek to extract the parameters of an assumed transistor model from certain voltage regions in the output or/and transfer characteristics of an individual TFT, [9][10][11][12][13] whereas in 'channel-length-scaling approaches' parameters are extracted from a series of nominally equivalent TFTs, that differ only in the channel length, by exploring the scaling of the transistor performance with the channel length from the perspective of the assumed model. [14][15][16] Neither of these two approaches is able to provide a reliable check of the consistency between theoretical model and measured current-voltage characteristics.…”

Section: Introductionmentioning

confidence: 99%

Critical Evaluation of Organic Thin-Film Transistor Models

et al. 2019

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Thin-film transistors (TFTs) represent a wide-spread tool to determine the charge-carrier mobility of materials. Mobilities and further transistor parameters like contact resistances are commonly extracted from the electrical characteristics. However, the trust in such extracted parameters is limited, because their values depend on the extraction technique and on the underlying transistor model. We propose a technique to establish whether a chosen model is adequate to represent the transistor operation. This two-step technique analyzes the electrical measurements of a series of TFTs with different channel lengths. The first step extracts the parameters for each individual transistor by fitting the full output and transfer characteristics to the transistor model. The second step checks whether the channel-length dependence of the extracted parameters is consistent with the model. We demonstrate the merit of the technique for distinct sets of organic TFTs that differ in the semiconductor, the contacts, and the geometry. Independent of the transistor set, our technique consistently reveals that state-of-the-art transistor models fail to reproduce the correct channel-length dependence. Our technique suggests that contemporary transistor models require improvements in terms of charge-carrier-density dependence of the mobility and/or the consideration of uncompensated charges in the transistor channel.

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“…Contact resistance is one of the important factors that affect the linear region (low drain voltages) of the output characteristics of the OTFTs [26][27][28][29][30][31][32][33][34][35][36][37][38]. This type of resistance acts as a barrier to the injection of charge carriers in OTFTs, thereby influencing their functionality and performance.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, examining contact resistance is a serious process in order to enhance the OTFTs performance. In this regard, many methods have been proposed to investigate the contact resistance in OTFTs [26][27][28][29][30][31][32][33][34][35][36][37][38]. Among them, the transfer line method (TLM) is the most popular extraction method of contact resistance in OTFTs.…”

Section: Introductionmentioning

confidence: 99%

Study and Analysis of Simple and Precise of Contact Resistance Single-Transistor Extracting Method for Accurate Analytical Modeling of OTFTs Current-Voltage Characteristics: Application to Different Organic Semiconductors

Alghamdi

2021

Crystals

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Contact resistance (Rc) characterizes the interface of source-drain electrodes/organic semiconductors and controls the injection efficiency of carriers in organic thin-film transistors (OTFTs). This research paper presents and assesses two methods for extracting the value of the contact resistance from the measured current-voltage characteristics of OTFTs made with various p-type organic semiconductors as active layers. These two methods are the transition voltage method (TVM) and the transfer line method (TLM). The obtained Rc values by the TVM method are in fair agreement with those obtained by TLM, with a maximum percentage of difference around 10%, demonstrating the accuracy of the used transition-voltage method. An analytical model was employed to calculate output characteristics in the linear regime of OTFTs made with various organic semiconductors using the contact resistance values obtained by the transition voltage method. The calculated results are in reasonably good agreement with the experimental ones of each fabricated device, which affirms the ability of the used model to characterize the charge transport correctly in these types of devices. It can be concluded that the used TVM method is not only an easy and practical method, but also a precise way for extracting Rc in OTFTs produced using different organic semiconductor materials.

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Extraction of contact resistance and channel parameters from the electrical characteristics of a single bottom-gate/top-contact organic transistor

Cited by 9 publications

References 30 publications

Contact Resistance in Organic Field‐Effect Transistors: Conquering the Barrier

Contact Resistance in Organic Field‐Effect Transistors: Conquering the Barrier

Critical Evaluation of Organic Thin-Film Transistor Models

Study and Analysis of Simple and Precise of Contact Resistance Single-Transistor Extracting Method for Accurate Analytical Modeling of OTFTs Current-Voltage Characteristics: Application to Different Organic Semiconductors

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