Lateral Grain Growth of Amorphous Silicon Films With Wide Thickness Range by Blue Laser Annealing and Application to High Performance Poly-Si TFTs

Jin, Seonghyun; Choe, Younwoo; Lee, Suhui; Kim, Tae‐Woong; Mativenga, Mallory; Jang, Jin

doi:10.1109/led.2016.2518705

Cited by 53 publications

(48 citation statements)

References 21 publications

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“…5 (c), which show also good saturation and no current crowding, indicating good ohmic contacts. In addition, my other paper recently reported that the PMOS p-Si TFTs fabricated with SLG p-Si films with a wide thickness range also exhibit excellent performance [20].…”

Section: Resultsmentioning

confidence: 95%

P-7: High Performance LTPS Thin-film Transistors using Low Cost Polycrystalline Silicon by Blue Laser Annealing

Jin

Mativenga

Jang

2016

SID Symposium Digest of Technical Papers

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Crystallization of amorphous silicon (a-Si) to polycrystalline silicon (p-Si) by a continuous-wave blue laser diode of wavelength 445 nm is investigated for high throughput thin-film transistor applications (TFT). As the laser scan speed is changed at constant laser power, laser scanned p-Si films show three kinds of grain shape that can be distinguished according to grain growth mechanism: (1) solid phase crystallization (SPC), (2) partial melting growth (PMG), and (3) full melting growth (FMG). These three growth mechanisms are as a result of different laser irradiation time to a-Si and relative absorbed laser energy difference, therefore, they achieve different grain size and crystallinity. By using this blue laser annealing (BLA) system, we can obtain the high performance and low cost low temperature polycrystalline silicon (LTPS) TFTs with large grain size. Author KeywordsPolycrystalline silicon (p-Si); crystallization; thin-film transistor (TFT); blue laser annealing (BLA); super lateral growth (SLG); low temperature polycrystalline silicon (LTPS).

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Section: Resultsmentioning

confidence: 95%

P-7: High Performance LTPS Thin-film Transistors using Low Cost Polycrystalline Silicon by Blue Laser Annealing

Jin

Mativenga

Jang

2016

SID Symposium Digest of Technical Papers

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“…2. Resulting from the Gaussian laser beam profile, a few distinct regions are identified (Fig, 2(a)); fine grained Si and nano-poly crystallized Si near the edge, and crystal growth regime in the center [1]. No damage to the glass substrate has been found under optimal annealing condition.…”

Section: Crystal and Surface Morphologymentioning

confidence: 99%

“…The endless list of advantages of BLA facilitates the true "green manufacturing", and the total cost of ownership is expected to be at least two orders of magnitude lower than that of ELA. Finally, p-Si films produced by CW laser have shown higher mobility, far better than that by ELA [1,5]. The blue-diode laser light penetrates deeper, hence causing volumetric heating in the a-Si film.…”

Section: Introductionmentioning

confidence: 99%

“…Low temperature polycrystalline silicon (LTPS) is widely employed in the manufacturing of advanced display backplanes. Although the excimer laser annealing (ELA) is a popular process choice for LTPS, continuous wave (CW) laser annealing, in particular, blue diode laser annealing (BLA), is rising as a potential alternative to replace ELA [1][2][3], since ELA becomes less attractive in today's display manufacturing. First, ELA is not compatible with substrate sizes above Gen 6 (1.5 x 1.8 m) due to the limited width of the line-shaped beam of excimer laser (~1.3 m).…”

Section: Introductionmentioning

confidence: 99%

“…This plays a significant role in producing larger lateral crystal grains (> 10 µm) along the scanning direction rather than the thickness direction. Hence, the CW blue diode laser is able to crystalize a-Si films with large, lateral grains for a wide range of film thicknesses [1]. Table 1 compares the key merits of BLA and ELA.…”

Section: Introductionmentioning

confidence: 99%

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35.1: Blue‐Diode Laser Annealing of Amorphous Silicon Films for Low‐Cost, Large‐Scale Manufacturing of Advanced Displays

Park

Hong

Jung

et al. 2018

Symp Digest of Tech Papers

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Blue diode laser annealing (BLA) systems have been successfully developed for low‐temperature crystallization from amorphous silicon film on glass substrates. It is demonstrated that it can achieve high quality poly‐Si film with large grain sizes, as studied by optical microscopy, Raman spectroscopy and AFM measurements. The p‐channel poly‐Si TFT on glass using BLA exhibited the field‐effect mobility of 168.05 cm2/Vs and subthreshold swing of 220 mV/dec. BLA is scalable to large‐scale display manufacturing and significantly lowers the capital expense and operating cost, since diode lasers are highly reliable and rugged, remarkably efficient, and maintenance‐free, allowing 24/7 operations without the need of consumables. The BLA system consists of an array of high‐power blue diode lasers (λ ~ 450 nm) and beam‐shaping optics to produce a line‐shaped beam which can be scanned at high speed to anneal the Si film in a single scan, where the high scan speed minimizes thermal stress. The scan‐to‐scan is seamless to cover a large panel such as G6 or G8 without glass damage. The physical phenomena responsible for melting and recrystallization are explained by heat transfer simulations for process optimization.

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Remarkable Improvement in Foldability of Poly‐Si Thin‐Film Transistor on Polyimide Substrate Using Blue Laser Crystallization of Amorphous Si and Comparison with Conventional Poly‐Si Thin‐Film Transistor Used for Foldable Displays

Jeong

Lee

et al. 2020

Adv Eng Mater

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Highly robust poly-Si thin-film transistor (TFT) on polyimide (PI) substrate using blue laser annealing (BLA) of amorphous silicon (a-Si) for lateral crystallization is demonstrated. Its foldability is compared with the conventional excimer laser annealing (ELA) poly-Si TFT on PI used for foldable displays exhibiting field-effect mobility of 85 cm 2 (V s) À1 . The BLA poly-Si TFT on PI exhibits the field-effect mobility, threshold voltage (V TH ), and subthreshold swing of 153 cm 2 (V s) À1 , À2.7 V, and 0.2 V dec À1 , respectively. Most important finding is the excellent foldability of BLA TFT compared with the ELA poly-Si TFTs on PI substrates. The V TH shift of BLA poly-Si TFT is %0.1 V, which is much smaller than that (%2 V) of ELA TFT on PI upon 30 000 cycle folding. The defects are generated at the grain boundary region of ELA poly-Si during folding. However, BLA poly-Si has no protrusion in the poly-Si channel and thus no defect generation during folding. This leads to excellent foldability of BLA poly-Si on PI substrate.

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Lateral Grain Growth of Amorphous Silicon Films With Wide Thickness Range by Blue Laser Annealing and Application to High Performance Poly-Si TFTs

Cited by 53 publications

References 21 publications

P-7: High Performance LTPS Thin-film Transistors using Low Cost Polycrystalline Silicon by Blue Laser Annealing

P-7: High Performance LTPS Thin-film Transistors using Low Cost Polycrystalline Silicon by Blue Laser Annealing

35.1: Blue‐Diode Laser Annealing of Amorphous Silicon Films for Low‐Cost, Large‐Scale Manufacturing of Advanced Displays

Remarkable Improvement in Foldability of Poly‐Si Thin‐Film Transistor on Polyimide Substrate Using Blue Laser Crystallization of Amorphous Si and Comparison with Conventional Poly‐Si Thin‐Film Transistor Used for Foldable Displays

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