Emission spectra study of plasma enhanced chemical vapor deposition of intrinsic, n+, and p+ amorphous silicon thin films

2013 ◽  
Vol 1536 ◽  
pp. 133-138
Author(s):  
I-Syuan Lee ◽  
Yue Kuo

ABSTRACTThe PECVD intrinsic, n+, and p+ a-Si:H thin film deposition processes have been studied by the optical emission spectroscope to monitor the plasma phase chemistry. Process parameters, such as the plasma power, pressure, and gas flow rate, were correlated to SiH*, Hα*, and Hβ* optical intensities. For all films, the deposition rate increases with the increase of the SiH* intensity. For the doped films, the Hα*/SiH* ratio is a critical factor affecting the resistivity. The existence of PH3 or B2H6 in the feed stream enhances the deposition rate. Changes of the free radicals intensities can be used to explain variation of film characteristics under different deposition conditions.

2012 ◽  
Vol 576 ◽  
pp. 594-597 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Dewan Muhammad Nuruzzaman

A hot filament thermal chemical vapor deposition (CVD) reactor was used to deposit solid thin films on stainless steel 316 (SS 316) substrates at different flow rates of natural gas. The variation of thin film deposition rate with the variation of gas flow rate has been investigated experimentally. During experiment, the effect of gap between activation heater and substrate on the deposition rate has also been observed. Results show that deposition rate on SS 316 increases with the increase in gas flow rate. It is also observed that deposition rate increases with the decrease in gap between activation heater and substrate within the observed range. In addition, friction coefficient and wear rate of SS 316 sliding against SS 304 under different normal loads are also investigated before and after deposition. The experimental results reveal that improved friction coefficient and wear rate are obtained after deposition as compared to that of before deposition.


Author(s):  
Mohammad A. Chowdhury ◽  
Dewan M. Nuruzzaman ◽  
Mohammad L. Rahaman

Solid thin films have been deposited on carbon steel substrates in a chemical vapor deposition (CVD) reactor where natural gas, mostly methane (CH4), was used as a precursor gas. The effect of gas flow rate on the thin film deposition rate has been investigated experimentally. The effect of gap between activation heater and substrate on the deposition rate has also been observed. To do so, a hot filament thermal chemical vapor deposition unit is used. The flow rate of natural gas varies from 0.5 to 2 l/min at normal temperature and pressure (NTP) and the gap between activation heater and substrate varies from 4 to 6.5 mm. Results show that the deposition rate on carbon steel increases with the increase of gas flow rate. It is also seen that deposition rate increases with the decrease of gap between activation heater and substrate within the observed range. These results are analyzed by dimensional analysis to correlate the deposition rate with gas flow rate, surface roughness and film thickness. In addition, friction coefficient and wear rate of carbon steel sliding against SS 304 under different normal loads are also investigated before and after deposition. The obtained results reveal that in general, the values of friction coefficient and wear rate are lower after deposition than that of before deposition.


2011 ◽  
Vol 63 (6) ◽  
pp. 433-439 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Dewan Muhammad Nuruzzaman ◽  
Khaled Khalil ◽  
Mohammad Lutfar Rahaman

2011 ◽  
Vol 189-193 ◽  
pp. 2032-2036 ◽  
Author(s):  
Zhi Jian Wang ◽  
Xiao Feng Shang

Taking Silicon tetrachloride (SiCl4) and hydrogen (H2) as the reaction gas, by the method of plasma-enhanced chemical vapor deposition (PECVD), this paper simulates the deposition process of polycrystalline silicon thin film on the glass substrates in the software FLUENT. Three dimensional physical model and mathematics model of the simulated area are established. The reaction mechanism including main reaction equation and several side equations is given during the simulation process. The simulation results predict the velocity field, temperature distribution, and concentration profiles in the PECVD reactor. The simulation results show that the deposition rate of silicon distribution is even along the circumference direction, and gradually reduced along the radius direction. The deposition rate is about 0.005kg/(m2•s) at the center. The simulated result is basically consistent with the practical one. It means that numerical simulation method to predict deposition process is feasible and the results are reliable in PECVD system.


Author(s):  
James E. Maslar ◽  
William A. Kimes ◽  
Brent A. Sperling

Thin film vapor deposition processes, e.g., chemical vapor deposition, are widely used in high-volume manufacturing of electronic and optoelectronic devices. Ensuring desired film properties and maximizing process yields require control of the chemical precursor flux to the deposition surface. However, achieving the desired control can be difficult due to numerous factors, including delivery system design, ampoule configuration, and precursor properties. This report describes an apparatus designed to investigate such factors. The apparatus simulates a single precursor delivery line, e.g., in a chemical vapor deposition tool, with flow control, pressure monitoring, and a precursor-containing ampoule. It also incorporates an optical flow cell downstream of the ampoule to permit optical measurements of precursor density in the gas stream. From such measurements, the precursor flow rate can be determined, and, for selected conditions, the precursor partial pressure in the headspace can be estimated. These capabilities permit this apparatus to be used for investigating a variety of factors that affect delivery processes. The methods of determining the pressure to (1) calculate the precursor flow rate and (2) estimate the headspace pressure are discussed, as are some of the errors associated with these methods. While this apparatus can be used under a variety of conditions and configurations relevant to deposition processes, the emphasis here is on low-volatility precursors that are delivered at total pressures less than about 13 kPa downstream of the ampoule. An important goal of this work is to provide data that could facilitate both deposition process optimization and ampoule design refinement.


MRS Bulletin ◽  
1988 ◽  
Vol 13 (11) ◽  
pp. 18-21 ◽  
Author(s):  
Russell Messier

Thin film materials pervade our everyday life as transparent conductors in LCD watches and computer displays and in defrosters for automobiles... antireflection coatings for camera lenses… optical fibers for communication … architectural glass coatings for both color and energy efficiency… solar cells… decorative coatings on plastics such as for toys and automobiles parts… a whole host of electronic and optoelectronic devices… hard coatings for cutting tools, drill bits, and bearings … even metallic coatings inside potato chip bags to keep the chips crisp!Without thin films our lifestyles would be drastically different. And this trend toward increased use of thin film technology will only continue.The varied reasons for using thin films and the specific deposition processes for preparing them are often complex; but usually relate to function, cost, beauty, materials and energy efficiency, and performance. In addition to technological applications, scientists are finding thin films to be an invaluable tool for investigating new physical phenomena, even at the quantum level. For instance, two of the most important new materials—high temperature ceramic superconductors and diamond coatings — are currently being made by several thin film deposition processes in order to explore both their scientific and technological potential.Just 25 years ago the variety of deposition processes for preparing thin films was quite limited. Thin film scientists and technologists had at their disposal electrodeposition, elementary chemical vapor deposition, evaporation, and dc sputtering. Commercial equipment for electron-beam evaporation, a mainstay in the optical coatings industry, was just being developed. Most of the deposition processes reviewed in this and next month's MRS BULLETIN were either not commercially available or were not even conceived of then.


Author(s):  
M. Mostafizur Rahman ◽  
Shaon Talukdar ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Rasel Khan ◽  
Abdullah A. Masum ◽  
...  

A hot filament thermal chemical vapor deposition (CVD) reactor was used to deposit solid thin films on stainless steel 316 (SS 316) and stainless steel 201 (SS 201) substrates at different flow rates of acetylene (C2H2) gas. The variation of thin film deposition rate with the variation of gas flow rate has been investigated experimentally. During experiments are conducted under gas flow rate (1-5) lit/min gas flow rate, duration of deposition (10-60 min), pressure (0.2-1 bar), average surface roughness (0.3-1.05) µm and temperature 800 °C considered. Experimental results show that deposition rate on SS 316 and SS 201 increases with the increase in gas flow rate. The deposition rate also shows increasing trend with pressure and duration of deposition. Under the above mentioned experimental conditions deposition is found to be maximum of SS-316 compared to SS-201. In relation to roughness the maximum deposition is found at 0.5 microns but comparing the both materials -316 and-201 highest of deposition rate is obtained from SS-316.


2006 ◽  
Vol 321-323 ◽  
pp. 1691-1694
Author(s):  
Mikio Noda ◽  
Masayoshi Umeno ◽  
Hee Joon Kim

Optical emission spectra from plasma during deposition of diamond film were investigated by an optic multi-channel spectrometer using a CCD array sensor. The diamond film was deposited by DC plasma enhanced (PE) chemical vapor deposition (CVD) using hydrogen and methane gas mixture, where substrate was located at near the plasma and the discharge was performed by intermittent discharge. When Pg during the deposition was increased from 50 to 250 Torr, the optical emissions of hydrogen (Hα and Hβ) and C2 were increased, and corresponding to these increases, deposition rate of the diamond film was increased and crystalline quality became superior. When Cm was changed from 1 to 3 %, the emission from C2 was increased, and whereas, the emission from hydrogen was decreased. Corresponding to these changes of the emission, the deposition rate of the film was increased and amorphous component in the deposited film was also increased. These results show that the increase of C2 results in the increase of the deposition rate, and increase of hydrogen is effective to eliminate amorphous component, and therefore, monitoring of the optical emission from hydrogen and C2 is useful for the deposition process of the diamond film.


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