Transistors and Technologies

Ellinger, Frank

doi:10.1007/978-3-540-69325-3_5

Cited by 8 publications

(17 citation statements)

References 44 publications

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“…Furthermore, the fabrication of radio frequency circuits generally requires only a very small number of fast TFTs along with additional long channel devices e.g. for biasing purposes [24]. Consequently, FIB TFTs combined with conventional transistors provides new opportunities for the fabrication of aggressively scaled flexible TFTs and analog circuits.…”

Section: Discussionmentioning

confidence: 99%

Focused ion beam milling for the fabrication of 160 nm channel length IGZO TFTs on flexible polymer substrates

Münzenrieder¹,

Shorubalko²,

Petti³

et al. 2020

Flex. Print. Electron.

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The quest for short channel length transistors is an important challenge in semiconductor industry. A similar trend is observed in the field of flexible electronics where sensor conditioning circuits and transceivers have to be realized on plastic foils. Here the use of a focused Ga + ion beam (FIB) to structure the channel of a flexible InGaZnO based thin-film transistor (TFT) is presented. The resulting flexible TFT exhibits a channel length of 160 nm and an effective field effect mobility of 4 cm 2 V =1 s =1 . Furthermore, the optimized Ga + beam milling does not damage the underneath Al 2 O 3 gate insulator leading to a gate leakage current of <200 pA. The extreme channel length demonstrates that focused ion beams can complement conventional fabrication approaches, overcoming current limitations imposed by flexible substrates. While the dimensions result in short channel effects and a drain conductance of 25 µS limiting the DC applicability of the FIB TFT, the device also exhibits a high internal gain of 3.4 dB. Consequently, a transit frequency of ≈6 MHz and a maximum frequency of oscillation of ≈19 MHz is measured for supply voltages ≤0.5 V. This shows that highly scaled flexible TFTs for analog circuits can be fabricated by ion beam milling.

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Section: Discussionmentioning

confidence: 99%

Focused ion beam milling for the fabrication of 160 nm channel length IGZO TFTs on flexible polymer substrates

Münzenrieder¹,

Shorubalko²,

Petti³

et al. 2020

Flex. Print. Electron.

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show abstract

“…A small‐signal frequency analysis was conducted to determine the transistor's admittance parameters, also known as Y‐parameters. [ 27 ] The currents are defined by the following matrix equation, in terms of the Y‐parameters matrix and the voltages:

\begin{equation} \delta i = Y \cdot \delta V \end{equation}

…”

Section: Resultsmentioning

confidence: 99%

High‐Frequency f_T and f_max in Organic Transistors: Performance and Perspective

Darbandy,

Pashaki,

Roemer

et al. 2024

Adv Elect Materials

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In state‐of‐the‐art organic transistors, the transit frequency fT is reported to be fT = 40 MHz for vertical organic transistors, where a voltage‐normalized fT corresponds to 0.36 MHz V−2. The reported highest fT for conventional organic transistors is fT = 160 MHz, where the voltage‐normalized fT is 0.1 MHz V−2. While the reported transit frequency fT of n‐MOSFETs for silicon technology when normalized by the applied biases exceeds 300 GHz V−2. The reported carrier mobility of organic semiconductors is over 100 cm2 V−1 s−1, which is almost an order of magnitude lower than that of silicon. However, the transit frequency fT of organic transistors lags far behind silicon technology by about six orders of magnitude at a comparable device length below 300 nm. In this work, a technology computer‐aided design (TCAD) simulator is adjusted to the experimental DC and AC characteristics of the 200 nm device length vertical organic permeable‐base transistors (OPBTs) based on C60 as semiconductor. The AC performance of the devices is investigated and quantitatively analyzed the influence and contribution of key design, structure and material parameters that determine fT and fmax. The feasible ways to enhance and optimize the highest achievable fT and fmax are identified to reach the and overcome the limitations to high‐frequency operation in organic transistors.

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“…The GaAs HEMT has substantial g m even at low currents, which varies approximately as the square root of current (10). Even when biased at ~0.1 mA, the low noise property of HEMT is still maintained.…”

Section: Methodsmentioning

confidence: 99%

Sensitivity Enhancement of an Inductively Coupled Local Detector Using a HEMT‐Based Current Amplifier

Cui

Duan

Dodd

et al. 2015

Magnetic Resonance in Med

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Purpose To improve the signal transmission efficiency and sensitivity of a local detection coil that is weakly inductively coupled to a larger receive coil. Methods The resonant detection coil is connected in parallel with the gate of a HEMT transistor without impedance matching. When the drain of the transistor is capacitively shunted to ground, current amplification occurs in the resonator by feedback that transforms a capacitive impedance on the transistor’s source to a negative resistance on its gate. Results High resolution images were obtained from a mouse brain using a small, 11 mm diameter surface coil that was inductively coupled to a commercial, phased array chest coil. Although the power consumption of the amplifier was only 88 µW, 14 dB gain was obtained with excellent noise performance. Conclusion An integrated current amplifier based on a High Electron Mobility Transistor (HEMT) can enhance the sensitivity of inductively coupled local detectors when weakly coupled. This amplifier enables efficient signal transmission between customized user coils and commercial clinical coils, without the need for a specialized signal interface.

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Transistors and Technologies

Cited by 8 publications

References 44 publications

Focused ion beam milling for the fabrication of 160 nm channel length IGZO TFTs on flexible polymer substrates

Focused ion beam milling for the fabrication of 160 nm channel length IGZO TFTs on flexible polymer substrates

High‐Frequency f_T and f_max in Organic Transistors: Performance and Perspective

Sensitivity Enhancement of an Inductively Coupled Local Detector Using a HEMT‐Based Current Amplifier

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Transistors and Technologies

Cited by 8 publications

References 44 publications

Focused ion beam milling for the fabrication of 160 nm channel length IGZO TFTs on flexible polymer substrates

Focused ion beam milling for the fabrication of 160 nm channel length IGZO TFTs on flexible polymer substrates

High‐Frequency fT and fmax in Organic Transistors: Performance and Perspective

Sensitivity Enhancement of an Inductively Coupled Local Detector Using a HEMT‐Based Current Amplifier

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Product

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High‐Frequency f_T and f_max in Organic Transistors: Performance and Perspective