Process and Material Properties Of PECVD BoronDoped Amorphous silicon Film'

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Process and Material Properties Of PECVD
Boron-Doped Amorphous silicon Film.

• Abstract Authors Helinda Nominanda and Yue Kuo.

Presented by Chakravarthy
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Thin Film Microelectronics Research
LaboratoryDepartment of Chemical
EngineeringTexas AM University,College
Station,TX.
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The effect of temperature and dopant gas flow on
PECVD boron-doped amorphous silicon film
properties such as deposition rate and
resistivity were studied.
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Deposition Process.

• Films were deposited at 50 KHz using a cold wall
  reactor with horizontal electrodes.
• A 2000 Angstrom thick PECVD silicon nitride film
  was deposited on a glass substrate as an adhesion
  layer.
• Temperature of 100-300 degree Celcius
• 40-200 sccm of diborane 400 sccm of hydrogen
  35 sccm silane(99.999)
• Pressure at 0.25 Torr
• Power density of 205 mW/sq.cm.

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The substrate temperature has a more pronounced
effect on the deposition rate than the dopant gas
flow rate.
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Resistivity decreases with temperature. A more
uniform resistivity is achieved at higher
temperatures.
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Applications of PECVD Amorphous Silicon Films.

• TFT arrays of active matrix liquid crystal
  display(AMLCDs)
• p-I-n junction capacitors
• Solar cells and Optoelectronic devices.

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Summary

• Deposition parameters have huge impact on the
  material properties of the PECVD boron-doped
  amorphous silicon films.