A ferroelectric semiconductor field-effect transistor

Abstract

A ferroelectric semiconductor field-effect transistor (FeS-FET) was proposed and experimentally demonstrated for the first time. In this novel FeS-FET, a two-dimensional (2D) ferroelectric semiconductor α-In2Se3 is used to replace conventional semiconductor as channel.α-In2Se3 is identified due to its proper bandgap, room temperature ferroelectricity, the ability to maintain ferroelectricity down to a few atomic layers and the feasibility for large-area growth.An atomic-layer deposition (ALD) Al2O3 passivation method was developed to protect and enhance the performance of the α-In2Se3 FeS-FETs. The fabricated FeS-FETs exhibit high performance with a large memory window, a high on/off ratio over 10 8 , a maximum on-current of 671 μA/μm, high electron mobility of 488 cm 2 /V•s, and the potential to exceed the existing Fe-FETs for non-volatile memory applications.

Two-dimensional ferroelectric channel transistors integrating ultra-fast memory and neural computing

“…The cross-sectional image and corresponding energy dispersive X-ray spectroscopy (EDS) element mapping at the interface between the multilayer h-BN and α-In2Se3 are shown in Figure 1c, which implies a clean van der Waals heterojunction with negligible interface state trapping effect. Figure 1d shows the Raman spectrum of the channel α-In2Se3 to characterize the material properties, which is consistent with previous reports, 14,18,30 and the peak at 89cm -1 suggests a hexagonal (2H) structure. 18 And the Figure S2b in Supporting Information.…”

“…5 Emerging memory devices such as memristors, 6 memtransistors, 7 phase change memory, 8 electrical double-layer transistors, 9 two-dimensional (2D) heterojunction devices, 10 and ferroelectric field effect transistors (FeFETs) 11 are used to perform analog computation in an attempt to break out of the dilemma. FeFETs with switchable electric dipoles, fast operation 12,13 and non-destructive readout 14 are ideal for building low-power, 12 high-efficiency memory computing integrated systems. However, traditional FeFETs use ferroelectrics as the dielectric layer to modulate channel conductance.…”

“…However, traditional FeFETs use ferroelectrics as the dielectric layer to modulate channel conductance. 14 The residual polarization decreases with cumulative switching cycles, and ferroelectric fatigue occurs, 15 resulting in memory with limited endurance. 16 In addition, the future trend of high-integration artificial intelligence applications is pushing the design of memory and computing elements toward miniaturization.…”

“…22 2D layered semiconductors with atomic thickness possess the potential for continuous shrinking, [23][24][25] which is a promising candidate for future high-density memory and computing systems. 26,27 Particularly, 2D layered α-In2Se3 exhibits robust ferroelectricity at room temperature (RT) without annealing, 14,28,29 and thanks to the intrinsic interlocking of dipoles in α-In2Se3, 18,22 it can maintain ferroelectric polarization even at atomic scale.…”

“…Crucially, we transferred the channel α-In2Se3 ferroelectrics onto a conductive Au/Al2O3 substrate and determined its ferroelectric polarization by piezoelectric microscopy (PFM). It is worth emphasizing that there is only polarization bound charges in the FeFETs, 14 which is reversed to achieve polarization switching, and finally modulate channel conductance (Figure 2a).…”