MSE PhD Prospectus Defense of Richard Lally
- Starts: 3:30 pm on Monday, November 13, 2017
- Ends: 5:30 pm on Monday, November 13, 2017
ABSTRACT: Quench condensed thin film (QCTF) materials are of continued experimental interest and have important electronic and optical device applications. Since the Fab on a Chip (FoC) deposition technique limits the surface mobility of atoms by significantly reducing their thermal energy, extremely thin uniform films can be achieved. While typical films of this thickness display insulator characteristics, the FoB QCTF can possess the electronic transport properties of a metal. Integrating MEMS components into a bonded stack of dies provides this unique in situ platform for conducting quench condensed thin film experiments.
"Atomic Calligraphy" provides the ability to create distinct nanoscale structures using a series of MEMS devices. The atomic calligraphy Fab on a Chip process incorporates sources, electrostatic comb driven writer plate, mass sensor, temperature sensor, and target surface into one multi-die assembly. Three separate dies are created using the PolyMUMPs process and can be flip-chip bonded together. Preassembly requires deposition of metal film on 50 x 50 μm2 joule heating source plates, thinning the writer plate die with a backside etch providing exposure to the 150 x 150 μm2 writer plate, and nanoscale apertures are milled on the writer plate using a FIB. The chip assembly is mounted in a cryogenic system (2.9 K) at ultra-high vacuum for depositing monolayers layers of atoms across targeted electrodes.
Using the FoC die set, in situ measurements can be conducted concerning the annealing, thickness, and temperature dependence of the metal’s Tc. Additional in situ experiments on the effect of thin film alloys or added magnetic impurities on their superconductivity can be measured with this process.
COMMITTEE: Advisor: David Bishop, MSE/ECE; Alice White, MSE/ME; Soumendra Basu, MSE/ME; Uday Pal, MSE/ME
- 110 Cummington Mall, Rm 205