In-line Process Monitoring for Amorphous Oxide Semiconductor TFT Fabrication using Microwave-detected Photoconductivity Decay Technique

Okuno, Hiroshi G.; Tao, Hiroaki; Morita, Shinya; Takanashi, Yasuyuki; Hino, Aya; Kishi, Tomoya; Ochi, Mitsukazu; Hayashi, Kazushi; Kugimiya, Toshihiro

doi:10.1587/transele.e97.c.1055

Cited by 13 publications

(12 citation statements)

References 22 publications

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“…Following the second component, a slow decay component appears with a decay constant in the order of microseconds. The mechanism of the slow decay component is attributed to the phenomenon that the laser-excited carriers are trapped at the localized states below the conduction band of the semiconductor thin film, and then de-trapped into the conduction band by thermal emission [ 16 ]. In general, the peak value and the slow decay time extracted from the

-PCD curves are performed to evaluate carrier trap defects in semiconductors.…”

Section: Resultsmentioning

confidence: 99%

Study of the Correlation between the Amorphous Indium-Gallium-Zinc Oxide Film Quality and the Thin-Film Transistor Performance

Ning

et al. 2021

Nanomaterials

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In this work, we performed a systematic study of the physical properties of amorphous Indium–Gallium–Zinc Oxide (a-IGZO) films prepared under various deposition pressures, O2/(Ar+O2) flow ratios, and annealing temperatures. X-ray reflectivity (XRR) and microwave photoconductivity decay (μ-PCD) measurements were conducted to evaluate the quality of a-IGZO films. The results showed that the process conditions have a substantial impact on the film densities and defect states, which in turn affect the performance of the final thin-film transistors (TFT) device. By optimizing the IGZO film deposition conditions, high-performance TFT was able to be demonstrated, with a saturation mobility of 8.4 cm2/Vs, a threshold voltage of 0.9 V, and a subthreshold swing of 0.16 V/dec.

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-PCD curves are performed to evaluate carrier trap defects in semiconductors.…”

Section: Resultsmentioning

confidence: 99%

Study of the Correlation between the Amorphous Indium-Gallium-Zinc Oxide Film Quality and the Thin-Film Transistor Performance

Ning

et al. 2021

Nanomaterials

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“…The μ‐PCD measurement is a very useful method to estimate mobility and defect‐like states in an oxide semiconductor film. In the μ‐PCD analysis, after photo‐excitation, the density of the carriers obey the following equation :

n true(t true) = n_{0} true{normale normalx normalp true(- \frac{t}{τ_{1}} true) + normale normalx normalp [- {false(\frac{t}{τ_{2}} false)}^{β}] true},

where n 0 is the carrier density just after photo‐excitation, τ 1 and τ 2 are the fast and slow decay constants, respectively, and β is the stretching exponent. Just after photo‐excitation, the peak value is indicated, and it is closely correlated with the mobility of the oxide film .…”

Section: Resultsmentioning

confidence: 99%

“…Just after photo‐excitation, the peak value is indicated, and it is closely correlated with the mobility of the oxide film . The term of slow decay ( τ 2 ) is mainly dominated by the re‐emission rate of the trapped carriers, serving information of shallow localized states . For the sample of μ‐PCD measurement, a mimicked sample of SiO 2 /Al‐IZTO/SiO 2 on glass substrate was prepared and annealed under the same conditions as the devices.…”

Section: Resultsmentioning

confidence: 99%

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Effect of a rapid thermal annealing process on the electrical properties of an aluminum‐doped indium zinc tin oxide thin film transistor

Nam

Yang

Jeong

et al. 2016

Physica Status Solidi (a)

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We report the effect of a rapid thermal annealing process (RTP) on the electrical properties of an aluminum‐doped indium zinc tin oxide (Al‐IZTO) thin film transistor (TFT) with a back‐channel etched (BCE) structure. First, the RTP temperatures were varied from 250 to 350 °C, and their effect on Al‐IZTO TFT was investigated. The 250 °C RTP produced the best transfer characteristics (subthreshold swing = 0.11 V/dec, hysteresis = −0.25 V, and mobility = 26.42 cm2 V−1s−1), and as the temperature increased, the TFTs showed slightly degraded properties in hysteresis and subthreshold swing. Through the transmission line method (TLM), the channel shortening effect and contact properties according to the annealing temperature were studied. The reliability against a negative gate bias stress under illumination (NBIS) was also analyzed. At high RTP temperature (>300 °C), stability under NBIS was considerably improved, and the 350 °C RTP device showed turn‐on voltage shift of −1.7 V. The microwave photoconductivity decay (μ‐PCD) method revealed that the RTP effectively reduced shallow localized states, which enhanced the NBIS stability at high temperature. Finally, the RTP was compared with the conventional furnace process at the same temperature in terms of transfer characteristics and uniformity. Even with a much shorter process time for the RTP, Al‐IZTO TFTs exhibited similar or better transfer properties and uniformity to or than the furnace annealing.

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“…Yasuno et al have reported the uniformity judgement of In-Ga-Zn-O (IGZO) on glass substrate by the µ-PCD measurement [15]. Goto et al implemented in-line process monitoring for the fabrication of a-IGZO TFTs using a microwave detected photoconductivity decay technique [16]. We introduce µ-PCD method to evaluate the homogeneity of dielectrics as well as defects between semiconductor/insulator interface by measuring IGZO film deposited on the top.…”

Section: Introductionmentioning

confidence: 99%

Effective Evaluation Strategy Toward Low Temperature Solution-Processed Oxide Dielectrics for TFT Device

Cai

Peng

Ning

et al. 2019

IEEE J. Electron Devices Soc.

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Solution-processed oxide dielectrics are widely studied as alternatives to SiO 2 , SiN x in thin film transistors for high capacitance and low energy consuming. However, it's still a challenge to achieve high quality of solution-processed oxide dielectrics TFT by low-temperature post-treatment. Here, an effective strategy is proposed to evaluate low temperature solution-processed ZrO 2 TFT in terms of uniformity, film density and electrical performance by employing TG/DSC, drop analyzer, XRR and a novel µ-PCD measurement. Particularly, µ-PCD measurement provides valuable information on homogeneity and defect level. The optimized device with ZrNO 3 as dielectric precursor and ethyl alcohol as solvent through spin coating process annealed at 200 • C shows a saturation mobility of 8.6 cm 2 V −1 S −1 , I on /I off ratio about 1.1×10 6 , subthreshold swing about 334 mV/decade with a low leakage current density of 5×10 −5 A/cm 2 at 10V. This article offers a convenient way for precursor optimization towards low leakage current and high homogeneity solution-processed oxide dielectrics for TFT devices.

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In-line Process Monitoring for Amorphous Oxide Semiconductor TFT Fabrication using Microwave-detected Photoconductivity Decay Technique

Cited by 13 publications

References 22 publications

Study of the Correlation between the Amorphous Indium-Gallium-Zinc Oxide Film Quality and the Thin-Film Transistor Performance

Study of the Correlation between the Amorphous Indium-Gallium-Zinc Oxide Film Quality and the Thin-Film Transistor Performance

Effect of a rapid thermal annealing process on the electrical properties of an aluminum‐doped indium zinc tin oxide thin film transistor

Effective Evaluation Strategy Toward Low Temperature Solution-Processed Oxide Dielectrics for TFT Device

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