Ultra high amorphous silicon passivation quality of crystalline silicon surface using in-situ post-deposition treatments

ABSTRACTThe as-deposited passivation quality of amorphous silicon films on crystalline silicon surfaces is dependent on deposition conditions and resulting hydrogen bonding structure. However the initial surface passivation can be significantly improved by low temperature post-deposition anneal. For example an improvement in effective lifetime from 780 μsec as-deposited to 2080 μsec post-anneal is reported in the present work. This work probes the hydrogen bonding environment using monolayer resolution Brewster angle transmission Fourier transform infrared spectroscopy of 100 Å thick films. It is found that there is significant restructuring at the a-Si:H / c-Si interface upon annealing and a gain of mono-hydride bonding at the c-Si surface is detected. Calculations show an additional 3.56 − 4.50 × 1014 cm−2 mono-hydride bonding at c-Si surface due to annealing. The estimation of the surface hydride oscillator strength in transmission mode is reported for the first time to be 7.2 × 10−18 cm on Si (100) surface and 7.5 × 10−18 cm on Si (111).

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Growth and Characterization of Single Crystal Epitaxial CoGa on MBE Grown III-V Semiconductors

MRS Proceedings ◽

10.1557/proc-144-613 ◽

1988 ◽

Vol 144 ◽

Author(s):

K. C. Garrison ◽

C. J. Palmstrøm ◽

R. A. Bartynski

Keyword(s):

Substrate Temperature ◽

Single Crystal ◽

Single Crystals ◽

Structural Quality ◽

High Quality ◽

Auger Analysis ◽

Post Deposition

ABSTRACTWe have demonstrated growth of high quality single crystal CoGa films on Ga1−xAlxAs. These films were fabricated in-situ by codeposition of Co and Ga on MBE grown Ga1−xAlxAs(100) surfaces. The elemental composition of the films was determined using Rutherford Backscattering (RBS) and in-situ Auger analysis. The structural quality of the films' surfaces was studied using RHEED (during deposition) and LEED (post deposition). RBS channeling was used to determine the bulk crystalline quality of these films.For ∼500 Å CoGa films grown at ∼450°C substrate temperature, channeling data showed good quality epitaxial single crystals [χmin ∼7%] with minimal dechanneling at the interface.

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Formation and Crystallization of Amorphous Silicides at the Interface Between Thin Metal and Amorphous Silicon Films

MRS Proceedings ◽

10.1557/proc-18-197 ◽

1982 ◽

Vol 18 ◽

Cited By ~ 2

Author(s):

S. R. Herd ◽

K. Y. Ahn ◽

K. N. Tu

Keyword(s):

Amorphous Silicon ◽

Amorphous Phase ◽

Crystalline Silicon ◽

Silicon Layer ◽

Diffraction Peak ◽

Gold Films ◽

Cubic Form ◽

No Formation ◽

Transmission Electron

We investigated the interaction of extremely thin (less than 10 nm) crystalline gold and rhodium films with amorphous silicon by transmission electron microscope in situ annealing. In thin Au/Si bilayers an amorphous phase with a diffraction peak at d ≂ 0.226 nm is formed by thermal annealing between 150 and 200 °C. Depending on the thickness and composition, silicon sputtered onto thin gold films leads to the formation of a layer of amorphous silicon and a partially amorphous Au-Si layer during deposition. The silicon layer crystallizes by itself at temperatures as low as 150 °C, and at 300 °C the amorphous Au–Si layer crystallizes into a metastable gold silicide (for silicon-rich compositions). In Rh/Si bilayers an amorphous Rh–Si phase is formed by annealing to 300 °C and can be detected by electron diffraction for a rhodium thickness of less than 5 nm and compositions with more than 50% Si if completely reacted. Above 300 °C the amorphous Rh-Si crystallizes preferentially in the cubic form of RhSi for intermediate silicon compositions and in the orthorhombic form of RhSi for high silicon compositions. Excess amorphous silicon is not found to have a lowered crystallization temperature when in contact with the amorphous Rh-Si alloy, and crystalline silicon is only observed above 730 °C together with the cubic and/or orthorhombic RhSi. In Rh/Si bilayers with a thicker rhodium layer, no formation of an amorphous phase was observed on annealing; instead crystalline Rh2Si forms during annealing above 300 °C.

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Effect of Hydrogenation Temperature on Distribution of Hydrogen Atoms in c-Si and a-Si: Molecular Dynamic Simulations

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.706.55 ◽

2016 ◽

Vol 706 ◽

pp. 55-59 ◽

Cited By ~ 1

Author(s):

Mauludi Ariesto Pamungkas ◽

Rendra Widiyatmoko

Keyword(s):

Amorphous Silicon ◽

Silicon Surface ◽

Prolonged Exposure ◽

Crystalline Silicon ◽

Transfer Hydrogenation ◽

Effect Of Temperature ◽

Hydrogen Atoms ◽

Dynamic Simulations ◽

Hydrogenation Temperature ◽

Dynamics Simulations

Crystalline silicon and amorphous silicon are main materials of solar cell. Under prolonged exposure to light, silicon will degrade in quality. Hydrogenation is believed can minimize this degradation by reduce the number of dangling bond. These Molecular dynamics simulations are aimed to elaborate the hydrogenation process of crystalline silicon and amorphous silicon and to elucidate effect of temperature on distribution of hydrogen atoms. Reactive Force Field is selected owing to its capability to describe forming and breaking of atomic bonds as well as charge transfer. Hydrogenation is performed at 300 K, 600 K, 900 K, and 1200 K. Hydrogenated silicon surface hinders further hydrogen atoms to be absorbed such that not all deposited Hydrogen atoms are absorbed by silicon surface. Generally, the higher hydrogenation temperature the more hydrogen atoms are absorbed. Increment of temperature from 900 K to 1200 K only enhances a few numbers of absorbed hydrogen atoms. However, it can enable hydrogen atoms to penetrate into deeper silicon substrate. It is also observed that hydrogen atoms can penetrate into amorphous silicon deeper than into crystalline silicon.

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A Particular Photo-CVD Apparatus for Hydrogenated Amorphous Silicon Deposition

MRS Proceedings ◽

10.1557/proc-258-165 ◽

1992 ◽

Vol 258 ◽

Author(s):

C. Manfredotti ◽

F. Fizzotti ◽

C. Osenga ◽

M. Boero ◽

V. Rigato ◽

...

Keyword(s):

Thin Films ◽

Amorphous Silicon ◽

Hydrogenated Amorphous Silicon ◽

Deposition Chamber ◽

Amorphous Thin Films ◽

Lock Chamber ◽

Hydrogenated Amorphous ◽

Deposited Films

ABSTRACTA new PHOTO-CVD apparatus has been built in order to deposit a – Si : H films and other kinds of amorphous thin films by a technique which is both simple and versatile. This apparatus is composed of three chambers connected together: a load-lock chamber, a process chamber and a third chamber for in-situ analysis of deposited films. A peculiarity of the lamp, a dielectric discharge lamp which can work with noble gases like Xe or Kr, is that it can be completely dismounted without breaking the vacuum in order to clean the optical MgF2 window. By this method, the deposition chamber can be kept in very clean conditions. In this apparatus, we started to deposit a – SixC1−x: H of very good quality, taking their thickness into account. These films have been completely characterized by chemical (RBS, ERDA) and optical (PDS) methods. Their quality can be compared with quality of a – Si : H samples of the same thickness obtained by PECVD.

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In Situ Fast Temperature Measurement of Silicon Thin Films during the Excimer Laser Annealing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.195 ◽

2006 ◽

Vol 326-328 ◽

pp. 195-198

Author(s):

Seung Jae Moon

Keyword(s):

Thin Films ◽

Optical Properties ◽

Melting Point ◽

Temperature Measurement ◽

Amorphous Silicon ◽

Laser Annealing ◽

Crystalline Silicon ◽

Excimer Laser Annealing ◽

Silicon Thin Films

The formation and growth mechanism of polysilicon grains in thin films via laser annealing of amorphous silicon thin films are studied. The complete understanding of the mechanism is crucial to improve the thin film transistors used as switches in the active matrix liquid crystal displays. To understand the recrystallization mechanism, the temperature history and liquidsolid interface motion during the excimer laser annealing of 50-nm thick amorphous and polysilicon films on fused quartz substrates are intensively investigated via in-situ time-resolved thermal emission measurements, optical reflectance and transmittance measurements at near infrared wavelengths. The front transmissivity and reflectivity are measured to obtain the emissivity at the 1.52 μm wavelength of the probe IRHeNe laser to improve the accuracy of the temperature measurement. The melting point of amorphous silicon is higher than that of crystalline silicon of 1685 K by 100-150 K. This is the first direct measurement of the melting temperature of amorphous silicon thin films. It is found that melting of polysilicon occurs close to the melting point of crystalline silicon. Also the optical properties such as reflectance and transmittance are used to determine the melt duration by the detecting the difference of the optical properties of liquid silicon and solid silicon.

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