Nanometer-Thick Oxide Semiconductor Transistor with Ultra-High Drain Current

Abstract

High drive current is a critical performance parameter in semiconductor devices for high-speed, low-power logic applications or high-efficiency, high-power, high-speed radio frequency (RF) analogue applications. In this work, we demonstrate an In2O3 transistor grown by atomic layer deposition (ALD) at back-end-of-line (BEOL) compatible temperatures with a record high drain current in planar FET, exceeding 10 A/mm, the performance of which is 2–3 times better than all known transistors with semiconductor channels. A high transconductance reaches 4 S/mm, recorded among all transistors with a planar structure. Planar FETs working ballistically or quasi-ballistically are exploited as one of the simplest platforms to investigate the intrinsic transport properties. It is found experimentally and theoretically that a high carrier density and high electron velocity both contribute to this high on-state performance in ALD In2O3 transistors, which is made possible by the high-quality oxide/oxide interface, the metal-like charge-neutrality-level (CNL) alignment, and the high band velocities induced by the low density-of-state (DOS). Experimental Hall, I–V, and split C–V measurements at room temperature confirm a high carrier density of up to 6–7 × 1013 /cm2 and a high velocity of about 107 cm/s, well-supported by density functional theory (DFT) calculations. The simultaneous demonstration of such high carrier concentration and average band velocity is enabled by the exploitation of the ultrafast pulse scheme and heat dissipation engineering.

Sub-5 nm Ultrathin In2O3 Transistors for High-Performance and Low-Power Electronic Applications

“…1a. 25 The outermost oxygen layers are passivated by hydrogen atoms to eliminate the surface dangling bonds. We chose the thinnest In 2 O 3 as our channel material, the thickness of which is 0.43 nm.…”

“…11 Moreover, an extremely high drain current (10 4 μA/μm) and transconductance (4000 μS/μm) are achieved in In 2 O 3 FETs with t of 3.5 nm. 25 Although ultrathin In 2 O 3 exhibits excellent device performance, the gate lengths (L g ) of almost all previously studied MOSFETs so far are larger than 10 nm except for the one with 8 nm L g and 2.5 nm t. The performance limit of ultrascaled In devices with sub-1 nm t and sub-5 nm L g , has yet to be comprehensively investigated.…”

“…However, their typical characteristics include relatively low carrier mobility (μ < 100 cm 2 ·V –1 ·s –1 ) and considerable thickness ( t of about several tens of nanometers for mass production) have limited applications in FETs. , Fortunately, the recent development of the atomic layer deposition (ALD) method has enabled the realization of ultrathin oxide semiconductors, such as indium oxide (In 2 O 3 ), with high carrier mobility (μ > 100 cm 2 ·V –1 ·s –1 ) and sub-1 nm thickness. ,− Experimentally, the sub-1 nm-thickness In 2 O 3 FETs exhibit a current on – off ratio of 10 6 , a maximum drain current of several hundred μA/μm, and a maximum transconductance of several hundred μS/μm . Moreover, an extremely high drain current (10 4 μA/μm) and transconductance (4000 μS/μm) are achieved in In 2 O 3 FETs with t of 3.5 nm . Although ultrathin In 2 O 3 exhibits excellent device performance, the gate lengths ( L g ) of almost all previously studied MOSFETs so far are larger than 10 nm except for the one with 8 nm L g and 2.5 nm t .…”

Review—Extremely Thin Amorphous Indium Oxide Transistors

“…Shaded areas represent the most desirable regions of device operation for logic transistors. Data sources: indium oxide, [106,[110][111][112][113] ITO, [100,142,99] IGZO, [143][144][145][146]97] IWO, [102,135] ZnO, [147] MoS 2 , [148][149][150][151][152][153][154][155][156] WS 2 , [157][158][159][160] Te, [161] WSe 2 , [162] black phosphorus, [163][164][165] GaN, [166] InGaAs, [167] InAs, [168] Si. [116] conditions [110] with disadvantages in process maturity, geometry (planar versus fin), and device scaling (40 nm channel length versus the 4 nm-equivalent node).…”

Reversible Charge Transfer Doping in Atomically Thin In2O3 by Viologens

“…Given its atomic-level uniformity, an ALD-based oxide semiconductor transistor using In 2 O 3 was developed, showing a maximum mobility of 100 cm 2 V −1 s −1 with a channel thickness down to 1 nm. 14 Additionally, the low sub-400 °C thermal aligned with existing silicon-based industrial methodologies, 15,16 unlocking the potential applications of atomically thin In 2 O 3 in monolithic 3D integrated circuits and sensors. 17 Adjusting charge carrier concentrations is essential in semiconductors for activating the functions of versatile electronics applications.…”