The RFET—a reconfigurable nanowire transistor and its application to novel electronic circuits and systems

Abstract

With CMOS scaling reaching physical limits in the next decade, new approaches are required to enhance the functionality of electronic systems. Reconfigurability on the device level promises to realize more complex systems with a lower device count. In the last five years a number of interesting concepts have been proposed to realize such a device level reconfiguration. Among these the reconfigurable field effect transistor (RFET), a device that can be configured between an n-channel and p-channel behavior by applying an electrical signal, can be considered as an end-of-roadmap extension of current technology with only small modifications and even simplifications to the process flow. This article gives a review on the RFET basics and current status. In the first sections state-of-the-art of reconfigurable devices will be summarized and the RFET will be introduced together with related devices based on silicon nanowire technology. The device optimization with respect to device symmetry and performance will be discussed next. The potential of the RFET device technology will then be shown by discussing selected circuit implementations making use of the unique advantages of this device concept. The basic device concept was also extended towards applications in flexible devices and sensors, also extending the capabilities towards so-called More-than-Moore applications where new functionalities are implemented in CMOS-based processes. Finally, the prospects of RFET device technology will be discussed.

Hardware Security For and Beyond CMOS Technology

“…Nanowire FETs (NWFETs) leverage nano-scaled and semiconductive wires as transistor channel. Various types of NWFETs have been studied, e.g., using silicon [132], indium arsenide [133], germanium, or even polymers [134] for materials; homogeneous or heterogeneous wire structures [135]; gate-all-around [136] or vertical gate structures [133]; et cetera-an overview can also be found in [135]. Conceptionally, NWFETs are somewhat similar to CNTFETs, but NWFETs allow for finer control of desired properties during manufacturing (albeit challenges for chip-scale manufacturing are there as well [135]), whereas CNT-FETs offer better performance [137].…”

Emerging reconfigurable nanotechnologies

“…Reconfigurability is the capability of a transistor to switch from p-channel to n-channel behavior through the application of a signal to an additional gate. Using Reconfigurable Field Effect Transistors (RFETs) allows for the development of more complex systems with fewer devices [34].…”

“…In recent years the use of multiple independent gates (MIGs) to connect FETs in series in a single device has been considered, as seen in [18,19,34], allowing for the elimination of interconnect effects. The MIG RFET also provides a wired-AND function to be used in many-input combinational circuits instead of the conventional XOR logic which is useful for transistor-level reconfiguration.…”

“…The MIG RFET also provides a wired-AND function to be used in many-input combinational circuits instead of the conventional XOR logic which is useful for transistor-level reconfiguration. These devices were originally made from silicon, though germanium has been used most recently with noticeable improvements; several types of RFETs are discussed in [18,19,34].…”

Reconfigurable vertical field-effect transistor based on graphene/MoTe2/graphite heterostructure

“…To overcome these challenges, reconfigurable FETs (RFETs) based on materials with ambipolar field-effect characteristics [1][2][3][4][5][6][7][8][9][10][11][12][13] that possess different operation modes and multiple functions, [14][15][16][17][18][19][20][21][22][23][24] were proposed as a promising solution to build multifunctional circuits with fewer compounds [16,[25][26][27][28]. Previously reported RFETs are based on a dual-gate planar structure [29][30][31]. The footprint of the RFETs has no advantage over that of the conventional FETs, which is undesirable to the high-density integration of RFETs.…”