Correlation between spin density and Vth instability of IGZO thin-film transistors

Park, Jee Ho; Lee, Sohyung; Lee, Hee Sung; Kim, Sung Ki; Park, Kwon‐Shik; Yoon, Soo‐Young

doi:10.1016/j.cap.2018.08.016

Cited by 5 publications

(3 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6 are mainly caused by the reduction in the IGZO channel thickness of the FPE-TFTs 23) as L becomes longer. Several previous works 26,27) have shown the same trend that a decrease in IGZO thickness leads to a more positive V th and a lowering in both SS and μ FE . Since the IGZO is an n-type semiconductor, the operation of IGZO TFTs is akin to that of junctionless (J-less) transistors: 28,29) As the channel is thinned down, the density of free electrons per gated area in the channel declines.…”

Section: I-v Characteristics Of Bg Igzo Tftssupporting

confidence: 56%

See 1 more Smart Citation

A low-temperature photoresist-based film-profile engineering scheme for fabricating bottom- and double-gated indium–gallium–zinc oxide TFTs

Liu,

Lin,

Chen

et al. 2024

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

We proposed a novel low-temperature (<110 oC) process scheme based on the film-profile engineering (FPE) technique for fabricating indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) with both bottom-gated (BG) and double-gated (DG) configurations. An organic photoresist (PR) suspended bridge is constructed to shadow the depositing species during the deposition processes of the bottom gate-oxide, channel, and source/drain metal films. An Al2O3 layer deposited at 110 °C using atomic-layer deposition (ALD) is employed as the bottom gate-oxide layer. Such a low-temperature process allows us to deposit the Al2O3 layer following the formation of the PR suspended bridge, preventing the formation of organic residues between the gate-oxide and channel layers. As a result, excellent device performance in terms of field-effect mobility of 12.1 cm²/V-s and subthreshold swing of 141 mV/dec is achieved. Our proposed low-temperature process scheme is readily applicable for fabricating DG TFTs which show substantial enhancements in driving currents.

show abstract

Section: I-v Characteristics Of Bg Igzo Tftssupporting

confidence: 56%

“…29) Reduction of the μ FE with reduced T c is presumably caused by an increase in the defect density in the channel as the channel is thinner. 27) We have also studied the hysteresis characteristics of the BG devices. An example is shown in Fig.…”

Section: I-v Characteristics Of Bg Igzo Tftsmentioning

confidence: 99%

A low-temperature photoresist-based film-profile engineering scheme for fabricating bottom- and double-gated indium–gallium–zinc oxide TFTs

Liu,

Lin,

Chen

et al. 2024

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…[ 43–45 ] However, for quaternary alloys such as IGZO, only a few studies on crystal IGZO and particle IGZO have been reported, [ 46 ] and there are still almost no reports on semiconductor materials such as quaternary alloys and non‐crystalline IGZO. [ 47 ] In this paper, we discuss the detailed ESR signal related to intrinsic defects of a‐IGZO, such as V o + , V Zn − , and the adsorption of oxygen ( O Adsorp ), which have not yet been reported, and defect behavior according to the fabrication process in insulating thin‐films. Owing to the limitations of the ESR technique, direct observations of the O–O dimer related to the peroxide model and H i of the hydrogen complex model are being studied using various spectroscopic techniques but are not covered in the present study.…”

Section: Introductionmentioning

confidence: 99%

Defect Engineering for High Performance and Extremely Reliable a‐IGZO Thin‐Film Transistor in QD‐OLED

Park

Cho

Kim

et al. 2022

Adv Elect Materials

View full text Add to dashboard Cite

organic light-emitting diode (QD-OLED) product based on an oxide thin-film transistor (TFT) using an amorphous oxide semiconductor, indium-gallium-zincoxide (a-IGZO), which it will soon release. The QD-OLED has a high color gamut (BT2020 > 90%) and has excellent advantages over liquid crystal displays (LCDs) or OLEDs (BT2020, ≈75%). In the case of blue light (415-455 nm), which is harmful to eyesight, it emits only half that of existing LCDs and ≈30% that of OLEDs, emitting the lowest level among current displays. Furthermore, QD-OLEDs exhibit the best performance in all picture quality fields, such as viewing angle, reflectivity, and contrast. [6] It is important to secure the electrical stability of oxide TFTs in order to achieve high resolution, high brightness, and long life. The TFTs of the QD-OLED with the active-matrix operation basically consist of driving TFTs and switching TFTs. In the case of driving TFTs, which always supply a constant current, electrical stability is required under constant current stress (CCS) and positive bias thermal stress (PBTS). In the case of switching TFTs with a long turn-off state, it is essential to secure the stability under negative bias thermal illumination stress (NBTIS). To date, studies on the mechanism related to electrical stability have been continuously conducted on oxide TFTs using various oxide semiconductors, such as ZnO, ZnSnO, InGaZnO, InZnSnO, ZrInZnO, etc. [2,[7][8][9][10][11][12][13][14] The oxygen vacancies or oxygen interstitial model, [15][16][17][18][19][20][21] peroxide model, [22][23][24][25][26] and hydrogen complex model [27][28][29][30][31][32][33][34][35] for the oxide semiconductor itself are proposed mechanisms for electrical instability. Furthermore, the interface and near-interface defects between the oxide semiconductor and the insulating film of the upper and lower parts of the oxide TFT are also known to cause instability. First, in the case of the oxygen vacancy model, three things are known of the energy level in the electronic structure or chemical energy (spatial coordination with cation). There is an oxygen vacancy with two trapped electrons V o 0 near the valence band, a single charged oxygen vacancy with one trapped electron V o + , and a doubly charged oxygen vacancy with no trapped electron V o 2+ near the conduction band. These oxygen defects are known to cause An amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT), which exhibits the best electrical stability (PBTS ≤ 0.009 V), is implemented to create quantum-dot organic light-emitting diode product. Electrical stability has been explained through various mechanisms involving defects related to oxygen and hydrogen. The defects of a-IGZO are identified and the parameters of the deposition process are utilized to obtain V o + and V Zn − values of 1.7 × 10 17 and 2.4 × 10 18 spins cm −3 , respectively, which are quantified using electron spin resonance for the first time. The defects of the gate insulator (GI) in the upper and lower parts of the a-IGZO TFT and ...

show abstract

Floating body effect in indium–gallium–zinc–oxide (IGZO) thin-film transistor (TFT)

Park,

Go,

Chae

et al. 2024

Sci Rep

View full text Add to dashboard Cite

In this paper, the floating body effect (FBE) in indium-gallium-zinc-oxide (IGZO) thin-film transistor (TFT) and the mechanism of device failure caused by that are reported for the first time. If the toggle AC pulses are applied to the gate and drain simultaneously for the switching operation, the drain current of IGZO TFT increases dramatically and cannot show the on/off switching characteristics. This phenomenon was not reported before, and our study reveals that the main cause is the formation of a conductive path between the source and drain: short failure. It is attributed in part to the donor creation at the drain region during the high voltage (Vhigh) condition and in part to the donor creation at the source region during the falling edge and low voltage (Vlow) conditions. Donor creation is attributed to the peroxide formation in the IGZO layer induced by the electrons under the high lateral field. Because the donor creation features positive charges, it lowers the threshold voltage of IGZO TFT. In detail, during the Vhigh condition, the donor creation is generated by accumulated electrons with a high lateral field at the drain region. On the other hand, the floating electrons remaining at the short falling edge (i.e., FBE of the IGZO TFT) are affected by the high lateral field at the source region during the Vlow condition. As a result, the donor creation is generated at the source region. Therefore, the short failure occurs because the donor creations are generated and expanded to channel from the drain and source region as the AC stress accumulates. In summary, the FBE in IGZO TFT is reported, and its effect on the electrical characteristics of IGZO TFT (i.e., the short failure) is rigorously analyzed for the first time.

show abstract

Correlation between spin density and Vth instability of IGZO thin-film transistors

Cited by 5 publications

References 20 publications

A low-temperature photoresist-based film-profile engineering scheme for fabricating bottom- and double-gated indium–gallium–zinc oxide TFTs

A low-temperature photoresist-based film-profile engineering scheme for fabricating bottom- and double-gated indium–gallium–zinc oxide TFTs

Defect Engineering for High Performance and Extremely Reliable a‐IGZO Thin‐Film Transistor in QD‐OLED

Floating body effect in indium–gallium–zinc–oxide (IGZO) thin-film transistor (TFT)

Contact Info

Product

Resources

About