Crystallization and doping of amorphous silicon on low temperature plastic

Patent · Sat Jan 01 00:00:00 EST 1994

OSTI ID:869492

Kaschmitter, James L ^[1]; Truher, Joel B ^[2]; Weiner, Kurt H ^[3]; Sigmon, Thomas W ^[4]

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1. Pleasanton, CA
2. Palo Alto, CA
3. Campbell, CA
4. Beaverton, OR

A method or process of crystallizing and doping amorphous silicon (a-Si) on a low-temperature plastic substrate using a short pulsed high energy source in a selected environment, without heat propagation and build-up in the substrate. The pulsed energy processing of the a-Si in a selected environment, such as BF3 and PF5, will form a doped micro-crystalline or poly-crystalline silicon (pc-Si) region or junction point with improved mobilities, lifetimes and drift and diffusion lengths and with reduced resistivity. The advantage of this method or process is that it provides for high energy materials processing on low cost, low temperature, transparent plastic substrates. Using pulsed laser processing a high (>900.degree. C.), localized processing temperature can be achieved in thin films, with little accompanying temperature rise in the substrate, since substrate temperatures do not exceed 180.degree. C. for more than a few microseconds. This method enables use of plastics incapable of withstanding sustained processing temperatures (higher than 180.degree. C.) but which are much lower cost, have high tolerance to ultraviolet light, have high strength and good transparency, compared to higher temperature plastics such as polyimide.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 5346850
• OSTI ID: 869492
• Country of Publication: United States
• Language: English

Related Subjects

crystallization
doping
amorphous
silicon
temperature
plastic
method
process
crystallizing
a-si
low-temperature
substrate
pulsed
energy
source
selected
environment
heat
propagation
build-up
processing
bf3
pf5
form
doped
micro-crystalline
poly-crystalline
pc-si
region
junction
improved
mobilities
lifetimes
drift
diffusion
lengths
reduced
resistivity
advantage
provides
materials
cost
transparent
substrates
laser
900
degree
localized
achieved
films
accompanying
rise
temperatures
exceed
180
microseconds
enables
plastics
incapable
withstanding
sustained
tolerance
ultraviolet
light
strength
transparency
compared
polyimide
pulsed energy
plastic substrate
method enables
diffusion length
ultraviolet light
amorphous silicon
energy source
pulsed laser
crystalline silicon
processing temperatures
substrate temperature
plastic substrates
substrate temperatures
laser processing
processing temperature
rate temperature
temperature rise
temperature plastic
energy processing
violet light
low-temperature plastic
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