Course Info | Class Notes | Evaluation / Check Marks | Labs | Class Schedule & Homework |
Course Description
This course introduces students to the theory and practice of high vacuum systems
as well as thin film deposition. Students will study the physical behaviour of gases
and the technology of vacuum systems including system operation and design.
Applications examined will include high-vacuum coating systems and gas laser tube filling where attention will be paid to issues of gas purity and sources of contamination. Thin film deposition technologies will also be covered including evaporation and sputtering techniques. Application of these technologies in fabricating optical coatings such as mirror, antireflective, and dielectric filter
coatings will be examined. This course includes a substantial laboratory component involving the processing of gas discharge and laser tubes (including contamination control), mass spectroscopy, and the design and fabrication of various thin film optical elements such as dielectric filters
and mirrors.
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The Physics of Gases and Vacuum Systems
Class Schedule
(completed/planned)
Laboratory work is a vital portion of this course. Whether experiencing first-hand the difficulties encountered while depositing thin films in a high-vacuum evaporator in the cleanroom (for example, controlling deposition rates manually on a thermal source and producing an accurate deposit thickness) or simply observing how an auto-ranging vacuum gauge operates in the spectroscopy lab, laboratory work provides hands-on skills not obtained from classroom work alone. Niagara is proud to have two unique dedicated lab spaces: the spectroscopy lab in V12 and the class-1000 cleanroom in V13C, both of which are utilized in this course.
As per departmental policy, late labs are assigned a mark of ZERO.
Lab1 - Gas Discharge Tubes
Using a turbomolecular high-vacuum system gas discharge tubes will be pumped. The effects of gas pressure on the discharge will be observed and the effect of impurities on the line spectrum of a discharge will be examined.
Sample Lab1 Marking Scheme as a PDF document. Marks are assigned to items identified in the lab outline as 'required' (refer to the lab outline for details)
Lab 2 - Pressure Measurement
A two week lab in which students alternate parts A and B in two consecutive weeks. Pressure measurement techniques for high-vacuum systems are examined. The performance of various roughing gauges will be investigated for accuracy over a given range and the effect of gas composition on gauge accuracy will be investigated. Residual gas analysis is then performed in which gas samples will be analyzed for isotopic purity using a quadrupole mass spectrometer - in addition to pure gases such as neon and carbon dioxide, air will be analyzed.
Sample Lab2 Marking Scheme as a PDF document. Marks are assigned to each question as shown.
Lab 3 - Gas laser tubes
Students will use a high-vacuum system (including turbomolecular pump and RGA) to evacuate and reprocess a helium-neon gas laser tube. Processing includes outgassing the tube by thermal and gas flushing methods. Students will be required to adjust pressure of the gas mix used (helium and neon) to optimize laser tube output. Once optimized, the tube will be sealed and monitored for long-term stability (i.e. the effects of residual gases in the tube such as trapped oxygen will be observed). Residual gas analysis will be used to show how gases evolve as the laser operates and E/P calculations will be performed comparing experimental to theoretical ratios for neon. As well, students will repump an argon-ion laser in order to experimentally determine the E/P ratio of argon gas.
Sample Lab3 Marking Scheme as a PDF document. Marks are assigned to each question as shown.
Lab 4 - Basic Thin Film Techniques: Thermal Evaporation Deposition
Students will operate a high-vacuum thermal deposition system to deposit a thin-film of aluminum onto glass substrates. During this lab students will be exposed to the operating principles of high-vacuum systems, practice working in a class-1000 cleanroom environment, gain experience controlling deposition rate by regulating filament current, and utilize in-process quartz crystal thickness monitoring to assure a proper film thickness.
Lab 5 - Optical Calibration of a Thin-Film monitor
Students will calibrate the tooling factors on a thin-film monitor by using optical means in which basic dielectric filters consisting of a layer of dielectric Na3AlF6 sandwiched between two thin layers of aluminum are fabricated. This structure, which resembles a Fabry-Perot interferometer, acts as a high-performance optical filter with a narrow spectral width. Filters will be modelled with thin film software, deposited in the cleanroom using the Bendix thermal evaporator, and filters will be analyzed by a Perkin-Elmer Lambda-3B spectrophotometer (in V12 outside the lab time). By correcting the model in software, the tooling factors for various substrate locations in the chamber will be determined.
PRELAB must be submitted to the lab instructor at least one-hour prior to the lab
Sample Lab Marking Scheme as a PDF document. Print and append as the last page of the lab report.
Lab 6 - Dielectric Mirrors (eBeam Deposition)
Students will design (using FilmStar software) then fabricate a QWOT multilayer dielectric mirror on 'Sparky', a 13kW eBeam deposition system. The resulting coating will be analyzed spectrographically.
PRELAB must be submitted to the lab instructor at least one-hour prior to the lab
The lab schedule is subject to change based on availability of laboratory equipment
