Modeling and control of a silicon substrate heater for carbon nanotube growth experiments

The precision engineering research group at MIT is working on carbon nanotube growth experiments on silicon substrates and in microfabricated silicon devices, to try to produce improved bulk nanotube growth. For this thesis, a heating control system was designed and implemented for eventual use in CNT growth experiments. The computer program that controls the heater is user-adaptable, so that an experimenter can easily change the desired temperatures at various points of the process. Later, this heating system will become part of a much larger system that also incorporates a controlled flow rate. The goal of the system is to achieve high-bandwidth control of reaction conditions. In the heating control system designed, a computer controls a power supply attached to a wire-wrapped silicon chip, which is used to heat up the system, and the temperature is measured by a thermocouple. The control algorithm uses proportional gain, and the output is a PWM voltage. For accurate control of the system, a goal was set out to achieve an error of within 10%. For gains above 5, the computer can accurately control the temperature to less than 5.5% of the desired values in steady state, and an error of 0.75% was achieved with a gain of 50.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Held, David (David A.)

Advisor dc:contributor.advisor

• Alexander H. Slocum.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/32891

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/32891