1
|
Park J, Go S, Chae W, Ryoo CI, Kim C, Noh H, Kim S, Du Ahn B, Cho IT, Yun PS, Bae JU, Park YS, Kim S, Kim DH. Floating body effect in indium-gallium-zinc-oxide (IGZO) thin-film transistor (TFT). Sci Rep 2024; 14:10067. [PMID: 38698148 PMCID: PMC11066109 DOI: 10.1038/s41598-024-60288-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/21/2024] [Indexed: 05/05/2024] Open
Abstract
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.
Collapse
Affiliation(s)
- Jingyu Park
- School of Electrical Engineering, Kookmin University, Seoul, 02707, Republic of Korea
| | - Seungwon Go
- Department of Electronic Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Woojun Chae
- Large Display Business Unit, LG Display Company, Paju, 10845, Republic of Korea
| | - Chang Il Ryoo
- Large Display Business Unit, LG Display Company, Paju, 10845, Republic of Korea
| | - Changwook Kim
- School of Electrical Engineering, Kookmin University, Seoul, 02707, Republic of Korea
| | - Hyungju Noh
- Department of Electronic Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Seonggeun Kim
- Department of Electronic Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Byung Du Ahn
- Large Display Business Unit, LG Display Company, Paju, 10845, Republic of Korea
| | - In-Tak Cho
- Large Display Business Unit, LG Display Company, Paju, 10845, Republic of Korea
| | - Pil Sang Yun
- Large Display Business Unit, LG Display Company, Paju, 10845, Republic of Korea
| | - Jong Uk Bae
- Large Display Business Unit, LG Display Company, Paju, 10845, Republic of Korea
| | - Yoo Seok Park
- Large Display Business Unit, LG Display Company, Paju, 10845, Republic of Korea
| | - Sangwan Kim
- Department of Electronic Engineering, Sogang University, Seoul, 04107, Republic of Korea.
| | - Dae Hwan Kim
- School of Electrical Engineering, Kookmin University, Seoul, 02707, Republic of Korea.
| |
Collapse
|
2
|
Kang WM, Cho IT, Roh J, Lee C, Lee JH. Low-Frequency Noise Characteristics in Multi-Layer WSe₂ Field Effect Transistors with Different Contact Metals. J Nanosci Nanotechnol 2019; 19:6422-6428. [PMID: 31026972 DOI: 10.1166/jnn.2019.17068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this work, we analyze characteristics of Ohmic, Schottky forward and reverse contact through a low-frequency noise (LFN) measurement, combining two types of metals (Pd and Au) as the source and drain (S/D) contacts that enable p-type properties in multi-layer WSe₂ field effect transistors (FETs). The LFN is one of the significant factors liming the performance of nano-scale devices such as TMDCs FETs having large surface-to-volume ratio. In addition, the LFN analysis, which relates to the device reliability, can help identify sensitive areas for current transport and evaluate the analog circuit applicability. Theoretically, the multi-layer WSe₂ has reasonable electron affinity and bandgap that can make p-channel FET using the metal with a relatively high work-function. However, it is experimentally confirmed that Schottky contact characteristics are exhibited in the multi-layer WSe₂ FETs with various metals except Pd due to the metal Fermi level pinning phenomenon. Mobility (μeff, ~87.5 cm²/V·s), one of the electrical performance extracted from fabricated devices with Pd as S/D electrodes shows a great difference from that (~0.572 cm²/V·s) of devices with Au as S/D electrodes. The measured electrical characteristics show that a Schottky contact is formed at an interface between Au and WSe₂ causing the higher LFN of the FETs than that of device with Pd as S/D electrodes. This characteristic is also verified by confirming the reduction of LFN due to the decreased effect of the Schottky property as the drain bias is increased.
Collapse
Affiliation(s)
- Won-Mook Kang
- Department of Electrical and Computer Engineering (EE) and Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, South Korea
| | - In-Tak Cho
- Department of Electrical and Computer Engineering (EE) and Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, South Korea
| | - Jeongkyun Roh
- Department of Electrical and Computer Engineering (EE) and Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, South Korea
| | - Changhee Lee
- Department of Electrical and Computer Engineering (EE) and Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, South Korea
| | - Jong-Ho Lee
- Department of Electrical and Computer Engineering (EE) and Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, South Korea
| |
Collapse
|
3
|
Hong SY, Kim HJ, Kim DH, Jeong HY, Song SH, Cho IT, Noh J, Yun PS, Lee SW, Park KS, Yoon S, Kang IB, Kwon HI. Study on the Lateral Carrier Diffusion and Source-Drain Series Resistance in Self-Aligned Top-Gate Coplanar InGaZnO Thin-Film Transistors. Sci Rep 2019; 9:6588. [PMID: 31036883 PMCID: PMC6488651 DOI: 10.1038/s41598-019-43186-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/16/2019] [Indexed: 11/09/2022] Open
Abstract
We investigated the lateral distribution of the equilibrium carrier concentration (n0) along the channel and the effects of channel length (L) on the source-drain series resistance (Rext) in the top-gate self-aligned (TG-SA) coplanar structure amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). The lateral distribution of n0 across the channel was extracted using the paired gate-to-source voltage (VGS)-based transmission line method and the temperature-dependent transfer characteristics obtained from the TFTs with different Ls. n0 abruptly decreased with an increase in the distance from the channel edge near the source/drain junctions; however, much smaller gradient of n0 was observed in the region near the middle of the channel. The effect of L on the Rext in the TG-SA coplanar a-IGZO TFT was investigated by applying the drain current-conductance method to the TFTs with various Ls. The increase of Rext was clearly observed with an increase in L especially at low VGSs, which was possibly attributed to the enhanced carrier diffusion near the source/drain junctions due to the larger gradient of the carrier concentration in the longer channel devices. Because the lateral carrier diffusion and the relatively high Rext are the critical issues in the TG-SA coplanar structure-based oxide TFTs, the results in this work are expected to be useful in further improving the electrical performance and uniformity of the TG-SA coplanar structure oxide TFTs.
Collapse
Affiliation(s)
- Sae-Young Hong
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, Korea
| | - Hee-Joong Kim
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, Korea
| | - Dae-Hwan Kim
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, Korea
| | - Ha-Yun Jeong
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, Korea
| | - Sang-Hun Song
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, Korea
| | - In-Tak Cho
- Research and Development Center, LG Display, E2 Block LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, Korea
| | - Jiyong Noh
- Research and Development Center, LG Display, E2 Block LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, Korea
| | - Pil Sang Yun
- Research and Development Center, LG Display, E2 Block LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, Korea
| | - Seok-Woo Lee
- Research and Development Center, LG Display, E2 Block LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, Korea
| | - Kwon-Shik Park
- Research and Development Center, LG Display, E2 Block LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, Korea
| | - SooYoung Yoon
- Research and Development Center, LG Display, E2 Block LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, Korea
| | - In Byeong Kang
- Research and Development Center, LG Display, E2 Block LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, Korea
| | - Hyuck-In Kwon
- School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, Korea.
| |
Collapse
|
4
|
Roh J, Cho IT, Shin H, Baek GW, Hong BH, Lee JH, Jin SH, Lee C. Fluorinated CYTOP passivation effects on the electrical reliability of multilayer MoS₂ field-effect transistors. Nanotechnology 2015; 26:455201. [PMID: 26472092 DOI: 10.1088/0957-4484/26/45/455201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrated highly stable multilayer molybdenum disulfide (MoS2) field-effect transistors (FETs) with negligible hysteresis gap (ΔV(HYS) ∼ 0.15 V) via a multiple annealing scheme, followed by systematic investigation for long-term air stability with time (∼50 days) of MoS2 FETs with (or without) CYTOP encapsulation. The extracted lifetime of the device with CYTOP passivation in air was dramatically improved from 7 to 377 days, and even for the short-term bias stability, the experimental threshold voltage shift, outstandingly well-matched with the stretched exponential function, indicates that the device without passivation has approximately 25% larger the barrier distribution (ΔE(B) = k(B)T(o)) than that of a device with passivation. This work suggests that CYTOP encapsulation can be an efficient method to isolate external gas (O2 and H2O) effects on the electrical performance of FETs, especially with low-dimensional active materials like MoS2.
Collapse
Affiliation(s)
- Jeongkyun Roh
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Jin SH, Kang SK, Cho IT, Han SY, Chung HU, Lee DJ, Shin J, Baek GW, Kim TI, Lee JH, Rogers JA. Water-soluble thin film transistors and circuits based on amorphous indium-gallium-zinc oxide. ACS Appl Mater Interfaces 2015; 7:8268-8274. [PMID: 25805699 DOI: 10.1021/acsami.5b00086] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This paper presents device designs, circuit demonstrations, and dissolution kinetics for amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water-soluble materials, including SiNx, SiOx, molybdenum, and poly(vinyl alcohol) (PVA). Collections of these types of physically transient a-IGZO TFTs and 5-stage ring oscillators (ROs), constructed with them, show field effect mobilities (∼10 cm2/Vs), on/off ratios (∼2×10(6)), subthreshold slopes (∼220 mV/dec), Ohmic contact properties, and oscillation frequency of 5.67 kHz at supply voltages of 19 V, all comparable to otherwise similar devices constructed in conventional ways with standard, nontransient materials. Studies of dissolution kinetics for a-IGZO films in deionized water, bovine serum, and phosphate buffer saline solution provide data of relevance for the potential use of these materials and this technology in temporary biomedical implants.
Collapse
Affiliation(s)
- Sung Hun Jin
- †Department of Electronic Engineering, Incheon National University, Incheon 406-772, Korea
| | - Seung-Kyun Kang
- ⊥Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - In-Tak Cho
- §Department of Electrical Engineering, Seoul National University, Seoul 151-600, Korea
| | - Sang Youn Han
- ⊥Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ha Uk Chung
- ⊥Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Dong Joon Lee
- ⊥Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jongmin Shin
- §Department of Electrical Engineering, Seoul National University, Seoul 151-600, Korea
| | - Geun Woo Baek
- †Department of Electronic Engineering, Incheon National University, Incheon 406-772, Korea
| | - Tae-il Kim
- ∥Center for Neuroscience Imaging Research (CNIR), Institute of Basic Science (IBS), School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, Gyeonggi-do 440-746, Korea
| | - Jong-Ho Lee
- §Department of Electrical Engineering, Seoul National University, Seoul 151-600, Korea
| | - John A Rogers
- ‡Department of Materials Science and Engineering, Chemistry, Mechanical Science and Engineering, Electrical and Computer Engineering, Beckman Institute for Advanced Science and Technology, and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|