[labnetwork] MOCVD systems

Tue Sep 10 17:03:28 EDT 2013

Julia,

   We have installed quite a few MOCVD reactors at different Universities
and production facilities in different settings.  There are many nuances to
installing and operating a MOCVD reactor.  With so many different details to
discuss I will list the major ones in order of importance.  Without knowing
what type of material you will be growing I will list  the options that
would apply to all and note possible options for you.

Facilities:

Location, we have installed MOCVD reactors in non-clean room areas where the
reactors had a load lock.  If the system you are looking at has a load lock
you might want to consider saving your expensive cleanroom square footage
for a tool that requires it.  One note here, most reactors that utilize a
load lock (whether in  a clean room or not) require 5% (H2) forming gas to
condition the load lock.  Another key consideration is structure, these
units take up a lot of floor space and are heavy, make sure your structure
is rated to handle the weight, and plan ahead on how you are going to get it
from your loading dock to its final destination.

Exhaust,  the reactor will require some significant exhaust, make sure your
clean room (or other if not in a cleanroom) make-up air handler is ready to
make up the air that will be exhausted.  Another major concern for exhaust
is, the type rating on the exhaust.  Not knowing the requirements from your
EH&S department, it would be a good idea to review with them the gases you
will be using on the tool as well as well as the contents of the process
pump effluent, and whether or not you will be scrubbing your process
exhaust.

H2 Supply, you will need a large source of Hydrogen to operate this tool,
and the higher the quality the better.  If your campus has house Hydrogen or
a bulk source for it, your one step in the right direction.  We had one
customer (University) who tried running their reactor on a switch over panel
with a four cylinder manifold on each side of the switch over, this type of
setup caused them more problems and equipment repairs than if they had just
invested in a bulk source of Hydrogen.  

Power, most reactors such as this will require quite a bit of power,
typically 250 to 400 amps of 208V 3 phase power.  One major consideration,
if your reactor is purifying the Hydrogen with an older style Palladium
cell, you also might want to consider a UPS system for running the heaters
for the Palladium cell, on the older style ones, if they cool off too fast
they can crack the Palladium inside them and render them completely useless
(and they aren't cheap to replace ~ 50k).  The newer Palladium cells are a
little more robust and can withstand more abuse.  One other note, typically
the process pumps on these type of reactors run 24X7 due to the fact that
they quickly seize up when shut down and allowed to cool, so be prepared for
that also (process pumps for reactors are not cheap either).

Process Cooling water, MOCVD reactors require quite a bit of process cooling
water, if your facility has a good house PCW system then you are probably
ok, typical flow-rates are around 60 to 100 LPM at  17-25 degrees C
depending on manufacturer and reactor size.

Process Gas Delivery, without knowing what type of material you will be
growing (III-V, II-VI, IV, IV-V-VI, semiconductors) I can't say what type of
gas you will be using, but regardless of the type of semiconductor, you will
be installing some toxic gas systems to support them.  These gases will be
required to be in gas cabinets with high quality purge panels,  the gas
cabinets will require building exhaust also, the gas delivery lines will
have to be high quality electro-polished stainless steel, some gas types
will also be required to be coaxial style gas lines, the assembly method for
gas lines are required to be welded throughout.  Again, I would review all
required gases with your EH&S department to ensure you have the proper
equipment to support them.

Life Safety, you will be required to incorporate life safety systems to
monitor all spaces (gas cabinets, reactor, and people space) for the
presence of flammable gas, toxic gas (dependent on material type) and Oxygen
deficient atm. 

Process Exhaust, if you are going to be using scrubbers (typically activated
charcoal bed type), you will need a good maintenance program to stay on top
of the scrubber maintenance, these units require regeneration and periodic
charcoal changes.  If you will not be using process exhaust scrubbers, then
you need to make sure your process exhaust effluent is compatible with the
building exhaust system you will be connecting it to.  Also, depending the
material type grown your process exhaust lines may be required to be heated
to prevent buildup of process byproducts.

Operation:

Maintenance, as far as operation goes with these systems they do require
periodic maintenance which correlates to run time as with most semiconductor
processing equipment.  Without a good understanding of the material type you
will be growing it would be futile to mention different maintenance routines
and what is required.  I will say this much, if the required maintenance is
not performed when it is supposed to be done, it can cause process
deviations, equipment failures, and possible life safety issues.  Some
reactor processes require acid based cleaning of components on the reactor
chamber, you may need a wet bench to support this or a bench available for
cleaning.

Analytical tools, depending on the film type grown, you will need to the
proper analytical tools to measure the specific characteristics of the film
type that you are quantifying. 

Waste Stream, again, depending on the type of material grown you will
develop a waste stream that will need to be managed.

Those are the major thoughts when considering a MOCVD reactor, we have
helped many different customers achieve a cost effective solution with
regards to installation and startup of these systems, so don't let all the
details scare you.  We would be happy discuss any questions or concerns that
you might have.  Please feel free to contact us with any other questions or
concerns.

Thank you,

Craig Cheney

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From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu]
On Behalf Of Aebersold,Julia W.
Sent: Tuesday, September 10, 2013 9:45 AM
To: <labnetwork at mtl.mit.edu>
Subject: [labnetwork] MOCVD systems

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Hi there!  We are considering the installation of a Veeco E300 MOCVD system
into our cleanroom.  We have not had experience with this type of tool and
would like to ask the community if they have a system of this type in their
cleanroom or in another room due to its size.  Also, if you have any other
concerns about operations, nuances, difficulty of operation, maintenance
headaches, etc. I would be greatly appreciative. 

See everyone at UGIM 2014!

Cheers!

Julia Aebersold, Ph.D.

MNTC Cleanroom Manager

University of Louisville

2210 South Brook Street

Shumaker Research Building, Room 233

Louisville, KY  40292

(502) 852-1572

http://louisville.edu/micronano/

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