Observation of Hydrogen-Related Defect in Subgap Density of States and Its Effects Under Positive Bias Stress in Amorphous InGaZnO TFT

Jang, Jun Tae; Ko, Daehyun; Choi, Sung-Jin; Kim, Dong Myong; Kim, Dae Hwan

doi:10.1109/led.2021.3066624

Cited by 22 publications

(14 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, based on previous work, the subgap DOS of a-ZBTO was incorporated into the simulation framework . The DOS model used is formulated as follows: , g ( E ) = g TD ( E ) + g DD ( E ) + g DA ( E ) + g TA ( E ) = N TD × exp ( − E − E V k T TD ) + N DD × exp ( − ( E C − E DD − E k T DD ) 2 ) + N DA 0.25em × exp ( − ( E C − E DA − E k T DA ) 2 ) +…”

Section: Resultsmentioning

confidence: 99%

“…First, based on previous work, the subgap DOS of a-ZBTO was incorporated into the simulation framework . The DOS model used is formulated as follows: , where the total DOS g ( E ) consists of g TD (donor-like tail states), g DD (donor-like deep states), g DA (acceptor-like deep states), and g TA (acceptor-like tail states); N TD and N TA are the intercept densities at E V and E C , respectively; kT TD and kT TA are the characteristic energies of the exponential tail states near E V and E C , respectively; kT DD and kT DA are the characteristic energies of the Gaussian deep states near E V and E C , respectively; E DD and E DA are the center energies of the Gaussian DOS peak near E V and E C , respectively; and N DD and N DA are the densities at the central energies E DD and E DA , respectively, of the Gaussian distribution.…”

Section: Resultsmentioning

confidence: 99%

“…First, based on previous work, the subgap DOS of a-ZBTO was incorporated into the simulation framework. 5 The DOS model used is formulated as follows: 25,26 i k j j j j j y { z z z z z i k j j j j j j j i k j j j j j y { z z z z z y { z z z z z z z i k j j j j j j j i k j j j j j y The DOS model for ZBTO and device structures used in the TCAD simulation are illustrated in Figure S5a,b. The parameters used in the TCAD simulation are summarized in Table S1.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Organic/Inorganic Hybrid Top-Gate Transistors with Ultrahigh Electron Mobility via Enhanced Electron Pathways

Park

Lee

et al. 2022

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

The top-gate structure is currently adopted in various flat-panel displays because of its diverse advantages such as passivation from the external environment and process compatibility with industries. However, the mobility of the currently commercialized top-gate oxide thin-film transistors (TFTs) is insufficient to drive ultrahigh-resolution displays. Accordingly, this work suggests metalcapped Zn−Ba−Sn−O transistors with top-gate structures for inducing mobility-enhancing effects. The fabricated top-gate device contains para-xylylene (PPx), which is deposited by a low-temperature chemical vapor deposition (CVD) process, as a dielectric layer and exhibits excellent interfacial and dielectric properties. A technology computeraided design (TCAD) device simulation reveals that the mobility enhancement in the Al-capped (Zn,Ba)SnO 3 (ZBTO) TFT is attributed not only to the increase in the electron concentration, which is induced by band engineering due to the Al work function but also to the increased electron velocity due to the redistribution of the lateral electric field. As a result, the mobility of the Al-capped top-gate ZBTO device is 5 times higher (∼110 cm 2 /Vs) than that of the reference device. These results demonstrate the applicability of top-gate oxide TFTs with ultrahigh mobility in a wide range of applications, such as for high-resolution, large-area, and flexible displays.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Organic/Inorganic Hybrid Top-Gate Transistors with Ultrahigh Electron Mobility via Enhanced Electron Pathways

Park

Lee

et al. 2022

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

show abstract

“…Given that V o H acts as the major electron donor, the IGZO channel usually becomes heavily n-doped after atomic-layerdeposition (ALD)-based ferroelectric top-gated (TG) dielectric deposition since the ALD deposition chamber is typically hydrogen abundant [27], [28]. Although different postdeposition annealing (PDA) treatments for defects passivation or channel carrier concentration modulation for IGZO-based devices have been widely studied [29], [30], [31], the high sensitivity and complexity of the channel interface/bulk defects formation as a function of different process ambients (e.g., H 2 , N 2 , or O 2 ) render the PDA effects unreliable.…”

Section: Introductionmentioning

confidence: 99%

High-Performance Top-Gated and Double-Gated Oxide–Semiconductor Ferroelectric Field-Effect Transistor Enabled by Channel Defect Self-Compensation Effect

Chen

Hooda

Fang

et al. 2023

IEEE Trans. Electron Devices

View full text Add to dashboard Cite

In this article, we demonstrate a low-thermal budget defect-engineered process to achieve top-gated (TG) oxide-semiconductor ferroelectric field-effect transistors (FeFETs). The demonstrated TG FeFETs, with the channel length scaled down to 40 nm, exhibit a highly stabilized ferroelectric memory window (MW) of 2 V and a high current ON/OFF ratio of 10 6 . This is achieved by an engineered InGaZnO x (IGZO) and InSnO x (ITO) heterojunction channel that produces the defect self-compensation effect to passivate the intrinsic oxygen-deficient defects, existing in the indium-gallium-zinc-oxide (IGZO) channel interface and bulk. Effective interface/bulk defects passivation with good control of defect-induced channel carrier concentration has been notoriously difficult to achieve. Hence, realizing performant TG oxide-based FeFETs with back-end-of-line (BEOL) thermal budget constraints remains a fundamental challenge. Our study shows that heterojunction channel engineering on FETs and FeFETs can be a reliable solution to overcome this challenge. With such a technique, we can now enable double-gated (DG) ITO-IGZO FeFET and FETs. Such devices can enable BEOL-compatible reconfigurable nonvolatile logic switches that provide extremely low offstate leakage, high switch conductance ratio, and memory read-write disturb-free features.

show abstract

“…Density functional theory-based calculations have indicated a possible shallow donor state near (< 0.6 eV) from the conduction band minimum 22 and enhanced state density in hydrogen-rich devices has been reported to be observed in the range 0.2 − 0.6 eV from the conduction band minimum. 12,32 However, hydrogen incorporation in a-IGZO has also been repeatedly correlated with an increased response from states in the near valence band region of the subgap, 9,11,17,23,28,33 which at least one author 33 has suggested could be linked to OH −interaction.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen incorporation into amorphous indium gallium zinc oxide thin-film transistors

Mattson,

Vogt,

Wager

et al. 2021

Preprint

View full text Add to dashboard Cite

Within the subgap of amorphous oxide semiconductors like amorphous indium gallium zinc oxide (a-IGZO) are donor-like and acceptor-like states that control the operational physics of optically transparent thin-film transistors (TFTs). Hydrogen incorporation into the channel layer of a top-gate a-IGZO TFT exists as an electron donor that causes an observed negative shift in the drain current-gate voltage (I D − V G ) transfer curve turn-on voltage. Normally, hydrogen is thought to create shallow electronic states just below the conduction band mobility edge, with the donor ionization state controlled by equilibrium thermodynamics involving the position of the Fermi level with respect to the donor ionization energy. However, hydrogen does not behave as a normal donor as revealed by the subgap density of states (DoS) measured by the photoconduction response of top-gate a-IGZO TFTs to within 0.3 eV of the CBM edge. Specifically, the DoS shows a subgap peak above the valence band mobility edge growing at the same rate that I D − V G transfer curve measurements suggest that hydrogen was incorporated into the channel layer. Such hydrogen donor behavior in a-IGZO is anomalous and can be understood as follows: Non-bonded hydrogen ionization precedes its incorporation into the a-IGZO network as a bonded species. Ionized hydrogen bonds to a charged oxygen-on-an-oxygen-site anion, resulting in the formation of a defect complex denoted herein as,1− defect complex creates a spectrally-broad (∼0.3 eV FWHM) distribution of electronic states observed in the bandgap centered at 0.4 eV above the valence band mobility edge.

show abstract

Observation of Hydrogen-Related Defect in Subgap Density of States and Its Effects Under Positive Bias Stress in Amorphous InGaZnO TFT

Cited by 22 publications

References 31 publications

Organic/Inorganic Hybrid Top-Gate Transistors with Ultrahigh Electron Mobility via Enhanced Electron Pathways

Organic/Inorganic Hybrid Top-Gate Transistors with Ultrahigh Electron Mobility via Enhanced Electron Pathways

High-Performance Top-Gated and Double-Gated Oxide–Semiconductor Ferroelectric Field-Effect Transistor Enabled by Channel Defect Self-Compensation Effect

Hydrogen incorporation into amorphous indium gallium zinc oxide thin-film transistors

Contact Info

Product

Resources

About