Deposition and Crystallisation Behaviour of Amorphous Silicon Thin Films Obtained by Pyrolysis of Disilane Gas at Very Low Pressure

1994 ◽  
Vol 345 ◽  
Author(s):  
T. Kretz ◽  
D. Pribat ◽  
P. Legagneux ◽  
F. Plais ◽  
O. Huet ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Electrical Conductance ◽  
Chemical Vapor ◽  
Crystalline Fraction ◽  
Silicon Thin Films ◽  
Crystallisation Behaviour

AbstractHigh purity amorphous silicon layers were obtained by ultrahigh vacuum (millitorr range) chemical vapor deposition (UHVCVD) from disilane gas. The crystalline fraction of the films was monitored by in situ electrical conductance measurements performed during isothermal annealings. The experimental conductance curves were fitted with an analytical expression, from which the characteristic crystallisation time, tc, was extracted. Using the activation energy for the growth rate extracted from our previous work, we were able to determine the activation energy for the nucleation rate for the analysed-films. For the films including small crystallites we have obtained En ∼ 2.8 eV, compared to En ∼ 3.7 eV for the completely amorphous ones.

Low pressure chemical vapor deposition of B-N-C-H films from triethylamine borane complex

1995 ◽  
Vol 10 (2) ◽  
pp. 320-327 ◽  
Author(s):  
R.A. Levy ◽  
E. Mastromatteo ◽  
J.M. Grow ◽  
V. Paturi ◽  
W.P. Kuo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Apparent Activation Energy ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Index Of Refraction ◽  
Arrhenius Behavior ◽  
Pressure Chemical

In this study, films consisting of B-N-C-H have been synthesized by low pressure chemical vapor deposition using the liquid precursor triethylamine borane complex (TEAB) both with and without ammonia. When no NH3 is present, the growth rate was observed to follow an Arrhenius behavior in the temperature range of 600 to 800 °C with an apparent activation energy of 11 kcal/mol. A linear dependence of growth rate is observed as a function of square root of flow rate for the TEAB range of 20 to 60 sccm, indicating that the reaction rate is controlled by the adsorption of borane. The addition of NH3 to TEAB had the effect of lowering the deposition temperature down to 300 °C and increasing the apparent activation energy to 22 kcal/mol. Above 650 °C, the carbon concentration of the deposits increased significantly, reflecting the breakup of the amine molecule. X-ray diffraction measurements indicated the films to be in all cases amorphous. Infrared spectra of the films showed absorption peaks representing the vibrational modes of B-N, B-N-B, B-H, and N-H. The index of refraction varied between 1.76 and 2.47, depending on composition of the films. Films deposited with no NH3 above 700 °C were seen to be compressive while films below that temperature were tensile. In the range of 350 to 475 °C, the addition of NH3 to TEAB resulted in films that were mildly tensile, while below 325 °C and above 550 °C, the films were found to be compressive. Both the hardness and Young's modulus of the films decreased with higher temperatures, reflecting the influence of the carbon presence.

Doping Efficiency of N-Type a-Si:H Doped with a Liquid Organic Source

1993 ◽  
Vol 297 ◽  
Author(s):  
K. Gaughan ◽  
ZHAOHUI Lin ◽  
J.M. Viner ◽  
P.C. Taylor ◽  
P.C. Mathur
Keyword(s):  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Band Tail ◽  
Optical Gap ◽  
Heavily Doped ◽  
Pl Intensity

N-type amorphous silicon films were grown using a mixture of silane and tertiarybutylphosphine (TBP-C4H11P) vapor in a plasma enhanced chemical vapor deposition system. The concentration of TBP in silane was varied from 0 to 3% by volume. As expected, at low doping levels, the photoluminescence (PL) intensity associated with both the band-tail recombination (peak at 1.3 eV) and deep-defect recombination (peak at 0.8 eV) decreased as the impurity concentration increased, but for TBP concentrations > 0.1% the PL intensity increased again. For moderate doping levels the activation energy for conductivity leveled off at ∼ 0.2 eV. For concentrations of TBP > 0.1% the activation energy for dark conductivity increased. A shift in the optical gap was observed for the highest impurity concentrations due to the incorporation of carbon from the TBP. These results are interpreted as a pronounced decrease in the doping efficiency for heavily doped films (> 0.1%) perhaps influenced by the increased carbon concentration.

The Electrical Properties of In-situ Doped Polycrystalline Silicon Thin Films Grown by Electron Cyclotron Resonance Chemical Vapor Deposition at 250°C

1997 ◽  
Vol 472 ◽  
Author(s):  
Yeu-Long Jiang ◽  
Ruo-Yu Wang ◽  
Huey-Liang Hwang ◽  
Tri-Rung Yew
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Cyclotron Resonance ◽  
Polycrystalline Silicon ◽  
Electron Cyclotron Resonance ◽  
Dopant Concentration ◽  
Chemical Vapor ◽  
Silicon Thin Films

AbstractThe phosphorus doped polycrystalline silicon thin films were grown by Electron Cyclotron Resonance Chemical Vapor Deposition (ECR-CVD) at 250°C. The doping gas PH3 was in-situ added with SiH4 gas during the films deposition. All films were deposited with 90% hydrogen dilution ratio. The resistivity of the films is varied from 0.2 to 7Ω-cm and decrease as the PH3/SiH4 gas ratio increase from (3/100 to 7/100). From the SIMS data, the doping concentration is all about 1020cm-3. The activation energy is decreased from 0.35 eV to 0.12 eV as the dopant concentration increased from 0.8×10 20cm-3 to 4.7×10 20cm-3. From the Hall measurements, the carrier mobility is about 2∼4 cm2/V. sec, and the carrier concentration is the 0.5∼1% of the dopant concentration. The gain boundary trap density predicted by the trapping model is about 4×l013cm” 2-2

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