XeCl Excimer laser annealing used in the fabrication of poly-Si TFT's

Sameshima, Toshiyuki; Usui, S.; Sekiya, M.

doi:10.1109/edl.1986.26372

Cited by 472 publications

(201 citation statements)

References 2 publications

Supporting

Mentioning

199

Contrasting

Unclassified

Order By: Relevance

“…The excimer laser annealing (ELA) process with short pulses has been widely utilized to achieve a low processing temperature to produce a polycrystalline silicon thin film on a glass substrate. 10 This technique has also been utilized for oxide-semiconductor materials. Nakata et al reported the fabrication of a-IGZO TFTs by ELA process, which acted as a postannealing process, and the improvement of the TFTs characteristics by ELA, 11 suggesting that the ELA process is also a promising technique for improving the characteristics of oxide-semiconductor devices.…”

mentioning

confidence: 99%

Low temperature high-mobility InZnO thin-film transistors fabricated by excimer laser annealing

Fujii

Ishikawa

Ishihara

et al. 2013

Applied Physics Letters

View full text Add to dashboard Cite

In this study, we successfully achieved a relatively high field-effect mobility of 37.7 cm 2 /Vs in an InZnO thin-film transistor (TFT) fabricated by excimer layer annealing (ELA). The ELA process allowed us to fabricate such a high-performance InZnO TFT at the substrate temperature less than 50 C according to thermal calculation. Our analysis revealed that high-energy irradiation in ELA produced a mixed phase of InZnO and SiO 2 , leading to the deterioration of TFT characteristics. Oxide semiconductor films deposited by sputtering have recently attracted considerable attention in the fields of transparent and flexible electronics for next-generation displays, in comparison with conventional amorphous silicon-based materials. In particular, an In 2 O 3 -doped ZnO (IZO) thin film is widely recognized as a suitable oxide semiconductor since thin-films transistors (TFTs) with that material in the channel layer yield a higher field-effect mobility than amorphous InGaZnO (a-IGZO) TFTs. [1][2][3] In the case of the IZO film, the amorphous phase generally provides a high conductivity of about 400 X À1 cm À1 , which is much higher than the conductivity suitable for the TFT's channel layer. 4,5 The conductivity of this material can possibly be reduced by a thermal annealing process. 6,7 In previous reports, thermal annealing with a relatively high temperature of about 300 C has been proposed to produce operative IZO TFTs. 8,9 However, such a high-temperature process in postannealing limits the choice for plastic flexible substrates. The excimer laser annealing (ELA) process with short pulses has been widely utilized to achieve a low processing temperature to produce a polycrystalline silicon thin film on a glass substrate. 10 This technique has also been utilized for oxide-semiconductor materials. Nakata et al. reported the fabrication of a-IGZO TFTs by ELA process, which acted as a postannealing process, and the improvement of the TFTs characteristics by ELA, 11 suggesting that the ELA process is also a promising technique for improving the characteristics of oxide-semiconductor devices. In this study, we focused on an IZO TFT with a higher field-effect mobility than an a-IGZO TFT. We assumed that an ELA process crystallizes IZO with nanograins easily since this material has a lower crystallization temperature than a-IGZO 12,13 and that an IZO film composed of nanograins has better characteristics than a noncrystallized IZO TFT since carrier scattering is suppressed in the disordered film. We considered it is necessary to use a laser with a wavelength shorter than 400 nm, for the laser to be absorbed by the IZO film since IZO has a wide band gap (higher than 3 eV). 14 We used an XeCl excimer laser with a sufficiently short wavelength of 308 nm (photon energy: 4.02 eV) 15,16 and investigated the effects of the ELA process on the IZO TFT characteristics and film properties.A thermally oxidized SiO 2 film of 100 nm thickness was formed on a highly doped p-type silicon wafer (<0.002 X cm) as a gate insulator. IZO films with...

show abstract

mentioning

confidence: 99%

Low temperature high-mobility InZnO thin-film transistors fabricated by excimer laser annealing

Fujii

Ishikawa

Ishihara

et al. 2013

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…The µ-Czochralski (grain-filter) process Excimer laser crystallization (ELC) is a well-established method for producing polySi films on non-heat resistant substrates (10). As shown in Fig.…”

Section: Single-grain Si Tftsmentioning

confidence: 99%

Single Grain Si TFTs for RF and 3D ICs

Ishihara¹,

Baiano²,

Chen³

et al. 2009

ECS Trans.

View full text Add to dashboard Cite

Single-grain Si TFTs have been fabricated using accurate 2D location control of large Si grain with the µ-Czochralski process. TFTs fabricated inside the crystalline islands of 6 µm show a mobility (600cm 2 /Vs) as high as that of the SOI counterpart, despite of the low-temperature (<350 o C) process. By applying a tensile stress into the grain, the mobility surpasses even the SOI counterparts. We have succeeded in controlling crystallographic orientation of the location-controlled Si grains as well, by combination of metal induced lateral crystallization and the microCzochralski process. Owing to the orientation control, uniformity in device properties approaches to the level of the SOI counterpart. Using the high performance single-grain (SG) Si TFTs, we have fabricated RF amplifier. The cut-off frequency of the RF device is 5.5 GHz with a channel length of 1.5 µm. We have even succeeded to stack two SG-TFT layers with which CMOS inverters were fabricated. This will open several new applications in TFTs of RF wireless communication, 3D-ICs with device level integration, and flexible electronics.

show abstract

“…The technologies of polycrystalline silicon thin film transistors (poly-Si TFTs) have been markedly developed in the last 20 years. Sameshima et al developed excimer laser induced crystallization of amorphous silicon films formed on glass substrates [5]. They reported poly-Si TFTs using laser crystallization with a low processing temperature of 270°C.…”

Section: Introductionmentioning

confidence: 99%

Laser crystallization for large-area electronics

Sameshima

2009

Appl. Phys. A

View full text Add to dashboard Cite

Laser crystallization is reviewed for the purpose of fabrication of polycrystalline silicon thin film transistors (poly-Si TFTs). Laser-induced rapid heating is important for formation of crystalline films with a low thermal budget. Reduction of electrically active defects located at grain boundaries is essential for improving electrical properties of poly-Si films and achieving poly-Si TFTs with high performances. The internal film stress is attractive to increase the carrier mobility. Recent developments in laser crystallization methods with pulsed and continuous-wave lasers are also reviewed. Control of heat flow results in crystalline grain growth in the lateral direction, which is important for fabrication of large crystalline grains. We also report an annealing method using a high-power infrared semiconductor laser. High-power lasers will be attractive for rapid formation of crystalline films over a large area and activation of silicon with impurity atoms.

show abstract

XeCl Excimer laser annealing used in the fabrication of poly-Si TFT's

Cited by 472 publications

References 2 publications

Low temperature high-mobility InZnO thin-film transistors fabricated by excimer laser annealing

Low temperature high-mobility InZnO thin-film transistors fabricated by excimer laser annealing

Single Grain Si TFTs for RF and 3D ICs

Laser crystallization for large-area electronics

Contact Info

Product

Resources

About