Efficiency of silane gas generation in high-rate silicon etching by narrow-gap microwave hydrogen plasma

Ohmi, Hiromasa; Funaki, Takeshi; Kakiuchi, Hiroaki; Yasutake, Kiyoshi

doi:10.1088/0022-3727/49/3/035202

Cited by 9 publications

(8 citation statements)

References 44 publications

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“…1b). Volatile SiH x (x # 3) radicals and SiH 4 have been reported to be directly generated from the Si surface by atomic hydrogen etching 29,30 in addition to the decomposition of monosilane in the plasma. The OES evidence could not conrm the chemical transport of silicon since the SiH band (420 nm) is obscured by an adjacent CH band.…”

Section: Resultsmentioning

confidence: 99%

Carbon fibre production during hydrogen plasma etching of diamond films

2016

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Section: Resultsmentioning

confidence: 99%

Carbon fibre production during hydrogen plasma etching of diamond films

2016

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“…In this study, the microwave input power was used for plasma generation and the solid Si sources were attached to the electrode surfaces. In a previous study [8], it was found that an excessive gas residence time leads to saturation of the SiH 4 generation rate, which is caused by decomposition of the generated SiH 4 . The electrode length along the gas flow direction should thus be designed carefully.…”

Section: Concept Of the Slit-type Plasma Sourcementioning

confidence: 98%

“…Because the plasma can then be generated locally around the plasma gap and gas transfer in the plasma is dominated by continuum viscous flow, the reaction time, or the gas residence time in the plasma, can then be controlled precisely. In a previous study [8], we used a pipe-type electrode to generate the hydrogen plasma and investigated the basic etching behavior of this plasma. The results showed that the silane generation behavior was strongly dependent on the gas residence time in the plasma, and indicated that high-efficiency and high-rate SiH 4 generation could not be achieved by simply enlarging the plasma area.…”

Section: Introductionmentioning

confidence: 99%

On-site SiH₄ generator using hydrogen plasma generated in slit-type narrow gap

Takei¹,

Shinoda²,

Kakiuchi³

et al. 2018

J. Phys. D: Appl. Phys.

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We have been developing an on-site silane (SiH4) generator based on use of the chemical etching reaction between solid silicon (Si) and the high-density H atoms that are generated in high-pressure H2 plasma. In this study, we have developed a slit-type plasma source for high-efficiency SiH4 generation. High-density H2 plasma was generated in a narrow slit-type discharge gap using a 2.45 GHz microwave power supply. The plasma’s optical emission intensity distribution along the slit was measured and the resulting distribution was reflected by both the electric power distribution and the hydrogen gas flow. Because the Si etching rate strongly affects the SiH4 generation rate, the Si etching behavior was investigated with respect to variations in the experimental parameters. The weight etch rate increased monotonically with increasing input microwave power. However, the weight etch rate decreased with increasing H2 pressure and an increasing plasma gap. This reduction in the etch rate appears to be related to shrinkage of the plasma generation area because increased input power is required to maintain a constant plasma area with increasing H2 pressure and the increasing plasma gap. Additionally, the weight etch rate also increases with increasing H2 flow rate. The SiH4 generation rate of the slit-type plasma source was also evaluated using gas-phase Fourier transform infrared absorption spectroscopy and the material utilization efficiencies of both Si and the H2 gas for SiH4 gas formation were discussed. The main etch product was determined to be SiH4 and the developed plasma source achieved a SiH4 generation rate of 10 sccm (standard cubic centimeters per minute) at an input power of 900 W. In addition, the Si utilization efficiency exceeded 60%.

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“…26 Reported studies of the pressure impact on Ga, Si, and N desorption rate state that Ga and Si desorption are independent of pressure (<100 Torr), while N desorption enhances with pressure. 48,49 This suggests that increasing the pressure of H 2 plasma reduces the barrier for both Si 3 N 4 and GaN etching from the surface. It has also been reported that increasing H 2 -plasma power enhances etching depth, as expected.…”

Section: Growth Recipementioning

confidence: 99%

“…Si 3 N 4 and GaN can easily be decomposed to volatile products via Si + 4H ⇌ SiH 4 , 2N + 3H 2 ⇌ 2NH 3 , and 2Ga + H 2 ⇌ 2GaH reactions in an H 2 -plasma chamber. ,, It has been shown by Tiwari and Chang that higher pressures and longer growth times increase both lateral size and etch depth of pits in GaN . Reported studies of the pressure impact on Ga, Si, and N desorption rate state that Ga and Si desorption are independent of pressure (<100 Torr), while N desorption enhances with pressure. , This suggests that increasing the pressure of H 2 plasma reduces the barrier for both Si 3 N 4 and GaN etching from the surface. It has also been reported that increasing H 2 -plasma power enhances etching depth, as expected.…”

Section: Growth Recipementioning

confidence: 99%

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

Malakoutian

Ren

Woo

et al. 2021

Crystal Growth & Design

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Integration of diamond on GaN can ease the challenges associated with thermal management of GaN-based power amplifiers which need to base on highly scaled transistors to push toward higher frequencies at high powers for 5G networks. The integration of diamond was achieved by growing polycrystalline (PC) diamond on nitrogen-polar GaN. A standard 5 nm Si3N4 layer which forms the gate dielectric was used as an interlayer between diamond and the GaN channel for etching protection. Since diamond growth conditions involve high temperature and H2 plasma, it can easily decompose the underlying dielectric as well as the GaN channel and degrade the channel conductivity and hence the device performance. Due to the incompatibility of conventional growth recipes with thin dielectrics (<5 nm), a novel two-stage-three-step growth recipe was designed for PC diamond integration on top of nitrogen-polar GaN high-electron-mobility transistors in a H2/CH4-plasma environment. Using only H2 and CH4 in the chamber guarantees a higher-phase-purity diamond than chambers with added argon or nitrogen for lower substrate etching. This recipe maintains the performance of the two-dimensional-electron gas and provides a less columnar diamond structure with a larger grain size. Our observations were supported by scanning transmission electron microscopy and Hall mobility measurements using the van der Pauw technique before and after diamond growth. A mobility of ∼1250 cm2/V s, a sheet carrier concentration of ∼1.30 × 1013 cm–2, and a sheet resistivity of ∼380 Ω/□ were maintained after the growth of diamond. The anisotropy ratio has been decreased from 3.75 to 1.12 with this growth recipe. Using long channel devices, we measured the difference in the channel temperature, which decreased by more than 100 °C in the range of 10–24 W/mm power after the integration of the diamond on top of the device.

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Efficiency of silane gas generation in high-rate silicon etching by narrow-gap microwave hydrogen plasma

Cited by 9 publications

References 44 publications

Carbon fibre production during hydrogen plasma etching of diamond films

Carbon fibre production during hydrogen plasma etching of diamond films

On-site SiH₄ generator using hydrogen plasma generated in slit-type narrow gap

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

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Efficiency of silane gas generation in high-rate silicon etching by narrow-gap microwave hydrogen plasma

Cited by 9 publications

References 44 publications

Carbon fibre production during hydrogen plasma etching of diamond films

Carbon fibre production during hydrogen plasma etching of diamond films

On-site SiH4 generator using hydrogen plasma generated in slit-type narrow gap

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

Contact Info

Product

Resources

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On-site SiH₄ generator using hydrogen plasma generated in slit-type narrow gap