Helium Versus Hydrogen Dilution of Silane in the Deposition of Polymorphous Silicon Films: Effects on the Structure and the Transport Properties

2003 ◽  
Vol 762 ◽  
Author(s):  
O. Saadane ◽  
S. Lebib ◽  
A.V. Kharchenko ◽  
V. Suendo ◽  
C. Longeaud ◽  
...  
Keyword(s):  
Transport Properties ◽  
Deposition Rate ◽  
Diffusion Length ◽  
Good Alternative ◽  
Silicon Films ◽  
Rf Power ◽  
Hydrogen Incorporation ◽  
Hydrogen Dilution ◽  
Hole Diffusion Length ◽  
Hydrogen Effusion

AbstractWe compare the deposition rate, hydrogen incorporation and optoelectronic properties of hydrogenated polymorphous silicon films produced either by the decomposition of silane-hydrogen or of silane-helium mixtures. Our results clearly show that He dilution allows to drastically reduce the RF power needed to achieve the same deposition rate as in the case of H2 dilution. Infrared spectroscopy and hydrogen effusion experiments show clear differences in the hydrogen bonding and content in both series of films. Interestingly, both He and hydrogen dilution result in films with improved transport properties, in particular the hole diffusion length, with respect to standard amorphous silicon. These results indicate that He dilution is a good alternative to H2 dilution to prepare intrinsic layers for solar cells.

Performances of Nano/Amorphous Silicon Films Produced by Hot Wire Plasma Assisted Technique

1998 ◽  
Vol 507 ◽  
Author(s):  
I. Ferreira ◽  
H. Águas ◽  
L. Mendes ◽  
F. Fernandes ◽  
E. Fortunato ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Transport Properties ◽  
Oxygen Content ◽  
Hydrogen Content ◽  
Crystalline Silicon ◽  
Silicon Films ◽  
Hot Wire ◽  
Hydrogen Dilution ◽  
Nano Crystalline ◽  
Doped Silicon

ABSTRACTThis work reports on the performances of undoped and n doped amorphous/nano-crystalline silicon films grown by hot wire plasma assisted technique. The film's structure (including the presence of several nanoparticles with sizes ranging from 5 nm to 50 nm), the composition (oxygen and hydrogen content) and the transport properties are highly dependent on the filament temperature and on the hydrogen dilution. The undoped films grown under low r.f. power (≍ 4 mWcm−2) and with filament temperatures around 1850 °K have dark conductivities below 10−1Scm−1, optical gaps of about 1.5 eV and photo-sensitivities above 105, (under AM3.5), with almost no traces of oxygen content. N- doped silicon films were also fabricated under the same conditions which attained conductivities of about 10−2Scm−1.

Effect of hydrogen dilution on the deposition rate of hydrogenerated amorphous silicon films in a modified pulsed plasma discharge

1996 ◽  
Vol 68 (6) ◽  
pp. 835-837 ◽  
Author(s):  
C. Mukherjee ◽  
C. Anandan ◽  
Tanay Seth ◽  
P. N. Dixit ◽  
R. Bhattacharyya
Keyword(s):  
Amorphous Silicon ◽  
Deposition Rate ◽  
Plasma Discharge ◽  
Silicon Films ◽  
Pulsed Plasma ◽  
Hydrogen Dilution

The Effect of Hydrogen Dilution on the Deposition of Sige Alloys and the Device Stability

1991 ◽  
Vol 219 ◽  
Author(s):  
L. Yang ◽  
L. Chen ◽  
A. Catalano
Keyword(s):  
Ir Spectroscopy ◽  
Glow Discharge ◽  
Transport Properties ◽  
Diffusion Length ◽  
Light Exposure ◽  
Dc Glow Discharge ◽  
Dilution Ratio ◽  
Hydrogen Dilution ◽  
Device Stability ◽  
The Stability

ABSTRACTWe have studied the structural and transport properties of a-Si1−x Gex:H alloys made by DC glow discharge of SiH4 and GeH4 with substantial amount of H2 dilution. The dilution ratio, i.e. H2/(SiH4 + GeH4), was varied up to 40:1. IR spectroscopy revealed that H2 dilution greatly suppresses the tendency of forming microvoids due to Ge incorporation. Photoconductivity and ambipolar diffusion length, which represent transport properties of electrons and holes respectively, are also significantly improved by using H2 dilution. At a dilution ratio of 20:1, the electron υτ product reached 10-6 cm2/V at a bandgap 1.55 eV which is even larger than that of a device quality a-Si:H. Solar cells using alloy i-layers made with H2 dilution were fabricated. The stability of the devices under light exposure was found to be much improved with increasing H2 dilution, suggesting a strong correlation between the stability and the density of microvoids.

Improved transport properties of microcrystalline silicon films grown by HWCVD with a variable hydrogen dilution process

2008 ◽  
Vol 516 (5) ◽  
pp. 568-571 ◽  
Author(s):  
Chisato Niikura ◽  
Romain Brenot ◽  
Joelle Guillet ◽  
Jean-Eric Bourée
Keyword(s):  
Transport Properties ◽  
Silicon Films ◽  
Microcrystalline Silicon ◽  
Hydrogen Dilution

Intrinsic and Doped m c-Si:H TFT Layers using 13.56 MHz PECVD at 250°C

2004 ◽  
Vol 808 ◽  
Author(s):  
Czang-Ho Lee ◽  
Denis Striakhilev ◽  
Arokia Nathan
Keyword(s):  
Performance Improvement ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Rf Power ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Bias Stress ◽  
Hydrogen Dilution ◽  
Low Threshold

ABSTRACTUndoped and n+ hydrogenated microcrystalline silicon (μc-Si:H) films for thin film transistors (TFTs) were deposited at a temperature of 250°C with 99 ∼ 99.6 % hydrogen dilution of silane by standard 13.56 MHz plasma enhanced chemical vapor deposition (PECVD). High crystallinity m c-Si:H films were achieved at 99.6 % hydrogen dilution and at low rf power. An undoped 80 nm thick m c-Si:H film showed a dark conductivity of the order of 10−7 S/cm, the photosensitivity of an order of 102, and a crystalline volume fraction of 80 %. However, a 60 nm thick n+ μc-Si:H film deposited using a seed layer showed a high dark conductivity of 35 S/cm and a crystalline volume fraction of 60 %. Using n+ μc-Si:H films as drain and source contact layers in a-Si:H TFTs provides substantial performance improvement over n+ a-Si:H contacts. Finally, fully μ c-Si:H TFTs incorporating intrinsic m c-Si:H films as channel layers and n+ μc-Si:H films as contact layers have been fabricated and characterized. These TFTs exhibit a low threshold voltage and a field effect mobility of 0.85 cm2/Vs, and are far more stable under gate bias stress than a-Si:H TFTs.

scholarly journals Effect of hydrogen dilution on structure and optical properties of polycrystalline silicon films

2006 ◽  
Vol 55 (5) ◽  
pp. 2523
Author(s):  
Huang Rui ◽  
Lin Xuan-Ying ◽  
Yu Yun-Peng ◽  
Lin Kui-Xun ◽  
Zhu Zu-Song ◽  
...  
Keyword(s):  
Optical Properties ◽  
Polycrystalline Silicon ◽  
Silicon Films ◽  
Hydrogen Dilution ◽  
Polycrystalline Silicon Films

Transport Properties and TEM Observation of R.A.D. Polycristalline Silicon Films

1979 ◽  
pp. 750-758 ◽  
Author(s):  
A. Johan ◽  
J. Ayerza ◽  
D. Bielle-Daspet ◽  
A. Rocher ◽  
C. Fontaine
Keyword(s):  
Transport Properties ◽  
Silicon Films
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