Recystallization characteristics of polycrystalline silicon films amorphized by germanium ion implantation

Kang, Myeon-Koo; Akashi, Kenichi; Matsui, Takayuki; Kuwano, Hiroshi

doi:10.1016/0038-1101(94)00112-s

Cited by 12 publications

(4 citation statements)

References 8 publications

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“…Some recrystallized P-doped films implanted with various Ge doses were additionally annealed at 900 °C for 30 min in N 2 ambient to activate and to uniformalize dopants through the films in order to measure resistivity, carrier concentration and Hall mobility at room temperature using the van der Pauw method [-5]. grain growth length, respectively, plotted against the annealing time; this is described in our previous paper [4]. It is found that the nucleation rate for the films implanted with Ge ions at 1 x 1015 cm -2 decreases with increasing doping concentration.…”

Section: Methodsmentioning

confidence: 99%

“…Solid phase regrowth (SPR) of the LPCVD poly-Si films amorphized by Si ion implantation on SiO2 has been reported to be a useful method for preparing such poly-Si films [2,3]. On the other hand, it has been reported that retardation of nucleation and enhancement of grain growth by germanium (Ge)ion implantation is useful for the formation of recrystallized films with a larger grain size than in films prepared by Si ion implantation [4]. However, the recrystallization behaviour and electrical properties of poly-Si films implanted with Ge ions at different doses have not been clarified.…”

Section: Introductionmentioning

confidence: 99%

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Recrystallization behaviour and electrical properties of germanium ion implanted polycrystalline silicon films

Kang

Matsui

Kuwano

1996

J Mater Sci: Mater Electron

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The recrystallization behaviour of undoped and phosphorus-doped polycrystalline silicon films amorphized by germanium ion implantation at doses ranging from 1 × 101S to 1 x 10 l° cm -2 are investigated, and the electrical properties of phosphorus-doped films after recrystallization are studied. The phosphorus doping concentration ranges from 3 x 1018 to 1 x 102o cm-3. It is found that the nucleation rate decreases for undoped films and increases for phosphorus-doped films with increasing germanium dose; the growth rates decrease for both doped and undoped films. The decrease in nucleation rate is caused by the increase in implantation damage. The decrease in growth rate is considered to be due to the increase in lattice strain. The grain size increases with germanium dose for undoped films, but decreases for phosphorus-doped films. The dependence of the electrical properties of the recrystallized films as a function of phosphorus doping concentration with different germanium doses can be explained in terms of the grain size, crystallinity and grain boundary barrier height.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Recrystallization behaviour and electrical properties of germanium ion implanted polycrystalline silicon films

Kang

Matsui

Kuwano

1996

J Mater Sci: Mater Electron

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“…Given the upper limit of 600 C for processing on glass [6], the long anneal times (about 20 hrs or higher) at 600 C [1] make the process unattractive for manufacturing. Various techniques have been employed to shorten the crystallization time, such as metal-induced crystallization [7] germanium-induced crystallization [8], and plasma treatments before the crystallization [9]- [11]. These plasma treatments include electron cyclotron resonance (ECR) plasma with oxygen, helium, or hydrogen at 400 C [9], [11], and radio frequency (rf) hydrogen plasma at room temperature [10].…”

Section: Introductionmentioning

confidence: 99%

Thin-film transistors in polycrystalline silicon by blanket and local source/drain hydrogen plasma-seeded crystallization

Pangal

Sturm

Wagner

et al. 2000

IEEE Trans. Electron Devices

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Thin film n-channel transistors have been fabricated in polycrystalline silicon films crystallized using hydrogen plasma seeding, by using several processing techniques with 600 to 625 C or 1000 C as the maximum process temperature. The TFT's from hydrogen plasma-treated films with a maximum process temperature of 600 C, have a linear field-effect mobility of 35 cm 2 /Vs and an ON/OFF current ratio of 10 6 , and TFT's with a maximum process temperature of 1000 C, have a linear field-effect mobility of 100 cm 2 /Vs and an ON/OFF current ratio of 10 7. A hydrogen plasma has also then been applied selectively in the source and drain regions to seed large crystal grains in the channel. Transistors made with this method with maximum temperature of 600 C showed a nearly twofold improvement in mobility (72 versus 37 cm 2 /Vs) over the unseeded devices at short channel lengths. The dominant factor in determining the field-effect mobility in all cases was the grain size of the polycrystalline silicon, and not the gate oxide growth/deposition conditions. Significant increases in mobility are observed when the grain size is in order of the channel length. However, the gate oxide plays an important role in determining the subthreshold slope and the leakage current.

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“…Unfortunately, SPC processed at 600°C usually requires a long crystallization time of 20-60 h to ensure the formation of poly-Si films with large grain size, making it unattractive for manufacturing. 3,6 Various measures have been employed to shorten the crystallization time, such as metal-induced crystallization, 7 germanium-induced crystallization, 8 and plasma treatment before crystallization. 9,10 Of these methods, radio frequency ͑rf͒ hydrogen plasma treatment before crystallization can potentially introduce the least effects on device reliability as a result of the metallic impurity in the channel 7 and significantly reduce the crystallization time.…”

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confidence: 99%

Effects of NH[sub 3] Plasma Pretreatment before Crystallization on Low-Temperature-Processed Poly-Si Thin-Film Transistors

Fan

Yang

2006

J. Electrochem. Soc.

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NH 3 plasma pretreatment before crystallization was performed for the first time on low-temperature-processed ͑LTP͒ poly-Si thin-film transistors. Significant reduction in amorphous silicon crystallization time was demonstrated using a novel NH 3 plasma pretreatment before crystallization. This is due to the creation of seed nuclei by hydrogen depletion at the pretreated a-Si films as a result of the impinging of hydrogen radicals dissociated from the NH 3 plasma. Thus, the following solid-phase crystallization step comprises only the growth of crystalline grains from the nuclei which are formed by the NH 3 plasma pretreatment. The NH 3 plasma can also produce nitrogen radicals to improve device reliability and performance as a result of the formation of strong Si-N bonds in place of weak Si-H and/or Si-Si bonds. The proposed NH 3 plasma pretreatment before crystallization is a promising scheme to significantly decrease the crystallization time and raise the product throughput in the manufacturing process as well as simultaneously improving the performance and reliability of LTP poly-Si thin-film transistors.There is increasing interest in the use of low-temperature processed ͑LTP͒ polycrystalline silicon thin-film transistors ͑poly-Si TFTs͒ for application in large-area display electronics, such as active matrix liquid crystal displays ͑AMLCDs͒ 1 and active matrix organic light-emitting displays ͑AMOLEDs͒. 2 Their primary advantages over the conventional amorphous silicon ͑a-Si͒ TFTs lie in their high driving current and the availability of both n-and p-channel TFTs. These features facilitate the integration of highperformance complementary metal-oxide-semiconductor peripheral drivers with active switching elements on a single glass substrate, thus reducing the number of external connections for improved reliability and reduced cost. The channel films for these devices are typically deposited in an amorphous phase, which is then crystallized to become large-grain polysilicon phase with a low grainboundary density. Various techniques have been used to crystallize amorphous silicon into a large-grain polysilicon phase, namely, solid phase crystallization ͑SPC͒, 3 excimer laser crystallization, 4 and electron-beam-induced crystallization. 5 SPC annealing in a furnace is a widely used scheme because of its simplicity and low cost as well as its ability to produce a smooth interface and excellent uniform film with a high reproducibility. Unfortunately, SPC processed at 600°C usually requires a long crystallization time of 20-60 h to ensure the formation of poly-Si films with large grain size, making it unattractive for manufacturing. 3,6 Various measures have been employed to shorten the crystallization time, such as metal-induced crystallization, 7 germanium-induced crystallization, 8 and plasma treatment before crystallization. 9,10 Of these methods, radio frequency ͑rf͒ hydrogen plasma treatment before crystallization can potentially introduce the least effects on device reliability as a result of the metallic imp...

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Recystallization characteristics of polycrystalline silicon films amorphized by germanium ion implantation

Cited by 12 publications

References 8 publications

Recrystallization behaviour and electrical properties of germanium ion implanted polycrystalline silicon films

Recrystallization behaviour and electrical properties of germanium ion implanted polycrystalline silicon films

Thin-film transistors in polycrystalline silicon by blanket and local source/drain hydrogen plasma-seeded crystallization

Effects of NH[sub 3] Plasma Pretreatment before Crystallization on Low-Temperature-Processed Poly-Si Thin-Film Transistors

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