Transparent Amorphous Oxide Semiconductors for Display Applications

Approaches for 3D Integration Using Plasma‐Enhanced Atomic‐Layer‐Deposited Atomically‐Ordered InGaZnO Transistors with Ultra‐High Mobility

“…), 3D scale-down memory, logic devices, CMOS image sensors (CIS), [8] and power systems [9] has been attempted to break through the power-saving and scaledown threshold. [10,11] However, oxide semiconductors require a higher electron mobility (>100 cm 2 Vs −1 ) with a low subthreshold swing (SS < 100 mV dec −1 ), near-zero threshold voltage (V th ), and low off-current for 3D structured devices. Therefore, it is essential to develop indium-gallium-zinc-oxide (IGZO) semiconductor manufacturing methods and processes applicable to nanoscale 3D structures.…”

P‐8: Synthesis of Superior‐Performance InGaZnO Based on Ideal Reaction of Plasma Enhanced Atomic Layer Deposition†

“…Moreover, non-display fields such as memories (DRAM, 3D-NAND, etc. ), CMOS image sensors (CIS) and power systems can also adopt oxide semiconductors due to their extremely low off-current (≤10 -18 Aμm −1 ), 3D structure applicability, and wide bandgap [3]. However, for next generation display and non-display fields, OS require higher field effect mobility than 100 cm 2 V -1 s -1 to surpass the low-temperature polysilicon (LTPS).…”

Visualization of Mesoscopic Conductivity Fluctuations in Amorphous Semiconductor Thin-Film Transistors

“…The typical mobility of a-IGZO (around 1−10 cm 2 /V•s) resides in an intermediate window between that of highly disordered solids (<0.1−1 cm 2 /V•s) and good crystalline semiconductors (>10−100 cm 2 /V•s). [1][2][3][4][5]9,10 As a result, charge transport in a-IGZO cannot be fully described by either the thermally activated hopping mechanism or the extended-state band model. 12,13 An extended multiple trap and release (MTR) model has been proposed to help explain transport in amorphous oxide semiconductors.…”

“…Amorphous oxide semiconductors are promising material platforms for next-generation transparent and flexible displays because they can be deposited as large-area uniform thin films on plastic substrates at low temperatures. − Unlike the crystalline counterparts, amorphous materials do not exhibit long-range periodicity in the atomic arrangement, − which usually results in inferior electrical and optical properties. Nevertheless, decades of investigations have led to the discovery of amorphous semiconductors with material qualities sufficient for thin-film transistor (TFT) applications. , For instance, in the amorphous indium gallium zinc oxide (a-IGZO) system, it is believed that the electronic structures are dominated by the extended spherical s orbitals of heavy metal cations, which are insensitive to the distortion of chemical bonds in disordered structures. ,, This is in sharp contrast to hydrogenated amorphous silicon (a-Si:H) with strong spatial directivity of the sp 3 orbitals, where the bond-angle distortion leads to significant reduction of carrier mobility .…”

“…The typical mobility of a-IGZO (around 1–10 cm 2 /V·s) resides in an intermediate window between that of highly disordered solids (<0.1–1 cm 2 /V·s) and good crystalline semiconductors (>10–100 cm 2 /V·s). − ,, As a result, charge transport in a-IGZO cannot be fully described by either the thermally activated hopping mechanism or the extended-state band model. , An extended multiple trap and release (MTR) model has been proposed to help explain transport in amorphous oxide semiconductors . In several theoretical studies, the effect of structural disorders in a-IGZO is modeled as a broad distribution of shallow band-tail states and deep traps in the energy gap. − These localized states give rise to spatial variation of the band edge in the form of random potential barriers with a Gaussian distribution of heights .…”