[paper] Three-Gated Reconfigurable FETs

Giulio Galderisi, Christoph Beyer, Thomas Mikolajick, and Jens Trommer 

Insights into the Temperature Dependent Switching Behaviour of Three-Gated Reconfigurable Field Effect Transistors 

physica status solidi (a) DOI: 10.1002/pssa.202300019

NaMLab gGmbH Dresden (D) 

TU Dresden, Chair of Nanoelectronics, Dresden (D) 

Abstract: Three-Gated Reconfigurable Field Effect Transistors are innovative nanoelectronic devices that are rapidly and increasingly attracting substantial interest in several fields of application thanks to their inherent n-type/p-type reconfiguration capabilities. For this reason, it is of significant importance to acquire a deeper knowledge about the temperature ranges in which such devices can be operated and, at the same time, gather a better understanding of the physical mechanisms that are involved in their operation. To achieve this aim, in-depth observations about the functioning of such devices in an ultra-wide temperature range, spanning from 80 K to 475 K, were performed and are presented for their ambipolar and lowVT operation modes. In view of the data exhibited in this work, it is possible to assess the performances of Three-Gated Reconfigurable Field Effect Transistors within a considerable temperature span and finally provide significant insights on the temperature dependent physical mechanisms regulating their functionality.

FIG: a) Typical Three-Gated RFET transfer characteristic, showing both p-/n-type curves for lowVT and highVT operations together with the ambipolar mode. b) Cross-sectional depiction of a Three-Gated RFET. c) False-colored SEM image of fabricated RFET device, based on 60 nm wide nanochannel. d) Schematic band diagrams of the most relevant operation modes of a Three-Gated RFET: off-states for both lowVT and highVT modes are shown, together with the on-state, which is the same for both operations. e) Table summarizing the possible RFET operations: the highlighted ones will be analyzed in this paper. f) Three-Gated RFET fabrication process flow. g) Ambipolar transfer curves for p/n-type branches, obtained on a different set of devices: the shaded area around the solid line (mean) shows the standard deviation calculated on 50 measured devices. h,i) P-type and n-type transfer curves of the lowVT mode for different values of the drain voltage. l,m) P-type and n-type transfer curves of the lowVT mode for different values of the program voltage. In m) it is possible to observe a shift in the VT when the device is programmed at 1 V: this non-ideality is probably due to traps generated in the gate oxide during measurement. 

Acknowledgements: This work was supported in part by the State budget by the delegates of the Saxon State Parliament and in part by the German Research Foundation (DFG) within the projects number 326384402 and SPP2253 under project number 439891087. 

[paper] Analysis of 2D Transistors

Guoli Li, Zizheng Fan, Nicolas André, Member, IEEE, Yongye Xu, Ying Xia, Benjamín Iñíguez, Fellow, IEEE, Lei Liao, Senior Member, IEEE, and Denis Flandre, Senior Member, IEEE

Non-Linear Output-Conductance Function for Robust Analysis of Two-Dimensional Transistors

IEEE Electron Device Letters, 42(1), pp.94-97

DOI: 10.1109/LED.2020.3042212

Abstract: In this work, we explore the outputconductance function (G-function) to interpret the device characteristics of two-dimensional (2D) semiconductor transistors. Based on analysis of the device output conductance, the carrier mobility, and the channel as well as contact resistance are extracted. Thereafter the currentvoltage (IV) characteristics of black phosphorous (BP) and MoS2 transistors from room to low temperature are modeled and compared to experiments. The G-function model proves its reliability and accuracy in parameter extraction and IV modeling of 2D transistors, regardless of the n- or p- type, the short- or long-channel and the Schottky or Ohmic contact. Moreover, this works shows its high potential in the device modeling and further circuit design of the 2D transistors, requiring only few parameters and simulating precise IV characteristics.

G-Function Model (for Linear and Non-Linear Cases), the Rch and Rc can be calculated for both the Ohmic and Schottky contacts in the 2D transistors: 

Aknowlegement: This work was supported in part by the National Key Research and Development Program of China under Grant 2018YFA0703700; in part by the National Natural Science Foundation of China under Grant 61925403, Grant 61851403, and Grant 62004065; in part by the Hunan Natural Science Foundation under Grant 2020JJ5087; and in part by the Technology Program (Major Project) of Changsha under Grant kq1902042.