With innovative, custom-designed thin-film deposition equipment and an integrated glovebox system, the laboratory space at Mount Holyoke College offers students the opportunity to conduct cutting-edge research typically reserved for graduate students at top tier research universities.
Because our semiconducting films can be sensitive to oxygen and moisture, solar cell fabrication and testing occurs entirely within an inert nitrogen environment. Substrates are manipulated with gloves through the front windows of a set of interconnected, nitrogen-filled gloveboxes. Stacks of thin films are grown in successive steps until the solar cell structure is complete and ready for testing.
Two key design elements are convenience and ease-of-use. An interconnected set of three nitrogen-filled glovebox units is placed in the center of the lab, providing the essential device fabrication and characterization functionality. With the glovebox windows and gloves facing outward, the U shape configuration compliments the geometry of the room and permits easy access from any location in the lab. The centrally located equipment layout and seamless fabrication protocols allow students to focus their attention on learning and applying their own creativity.
Working closely with LC Technology Solutions Inc., the lab’s gloveboxes were designed and outfitted with a number of innovative features, including LED lighting, vented three-way miniature antechambers and centralized vacuum. The wet deposition glovebox contains an integrated miniature freezer, centrifuge and spin coater for quantum dot and polymer film deposition. The dry deposition glovebox contains an integrated thermal evaporation system and floor/sidewall mounts for additional deposition systems and chambers. The characterization glovebox holds an optical table directly beneath the glovebox floor, and contains electrical, fiber-optic and viewport feedthough ports mounted on the glovebox floor for easy access. Both the wet and dry deposition gloveboxes have low-profile HEPA filters, allowing for cleanroom-level particle counts within the gloveboxes.
To reduce noise and congestion inside the lab, the chiller, roughing pump and backing pump are located in a chase adjacent to the lab space. Overhead supply lines bring centralized roughing vacuum, backing vacuum, and chilled water into the lab. Exhaust ventilation and electricals are also mounted on the ceiling. The noise level within the lab is notably quiet, and equipment maintenance can be accomplished out of the way of experimentation setups.
Designed for simplicity and ease-of-use, the modified “torpedo” deposition chambers are mounted beneath the dry deposition glovebox floor. The chamber design is unique in its compact size, retractible base plate elevator system, side-mounted substrate rotation drive, easy top-loading substrate access and easy-to-clean internal sleeve design. The result is a low-cost system with fast pump down times, convenient substrate loading from within the glovebox, convenient source material loading from inside or outside the glovebox and painless cleaning procedures. The side-mounted substrate rotation drive frees up space within the glovebox for other activities. The chamber can be purchased from LC Technology Solutions.
Our custom-designed, facing-target sputter deposition system is capable of depositing metal oxide films on top of sensitive organic or colloidal quantum dot films, often a difficult task for traditional sputtering systems. The facing target configuration confines the plasma to the region between the targets, sputtering material off-axis toward substrates located overhead, safely out of range of the plasma. Two twin-gun assemblies mounted on rotational feedthroughs allow for the deposition of two materials or four alloys without opening the chamber. Target mounting is possible from both inside or outside the glovebox. For more information, see “Design of a radio-frequency facing-target sputtering system for low-damage thin film deposition” (Thesis, Sophia Weeks ’13). The system was designed by Sophia Weeks ’13 and Ednah Louie ’14 in conjunction with PVD products and LC Technology Solutions.