The long-term goal of this research project is the development of solution-based
inorganic dielectric and semiconductor materials for inkjet printed electronics.
The main focus of this thesis involves testing of the materials and devices
under development.
A new solution-based inorganic dielectric material (HfOSO₄), given the
name hafsox, is developed and shows excellent dielectric properties. Hafsox with
the addition of lanthanum, to improve film dehydration, has successfully been
demonstrated as a gate dielectric. Metal-insulator-metal (MIM) capacitance testing
of hafsox with lanthanum, has resulted in a low loss tangent of 0.30% at 1
kHz, a relative permittivity of 11.47 at 1 kHz, a breakdown voltage of 6.30 MV
cm⁻¹, and a leakage current density of 4.38 nA cm⁻² at 1 MV cm⁻¹.
Progress has also been achieved in the development of solution-based semiconductor
materials. To date the most successful of these materials is zinc indium
oxide (ZIO), which has been demonstrated as a thin-film-transistor (TFT) channel
material. This ZIO TFT is a depletion-mode device with a turn-on-voltage
of V[subscript on]~ -19 V, a threshold voltage of V[subscript T] ~-16 V, and a drain current on-to-off
ratio of ~10³. Mobilities extracted from this ZIO TFT include an incremental
mobility of μ[subscript inc] ~0.05 cm² V⁻' sec⁻', an effective mobility of μ[subscript eff] ~0.02 cm²
V⁻' sec⁻', and an average mobility of μ[subscript avg] ~0.02 cm² V⁻' sec⁻' at V[subscript GS]=20 V.
The development of metal-semiconductor field-effect transistors (MESFET)
TFTs is also investigated as a means of eliminating the need for a dielectric
material in order to reduce the complexity of fabricating circuits. MESFETs are
attempted with semiconductor materials such as CdS that is deposited by chemical
bath deposition (CBD) and SnO₂ that is deposited by RF magnetron sputtering,
but with little success. The most successful MESFET-like device fabricated, employing
SnO₂ as the channel material, is a strong depletion-mode device with a
small amount of gate voltage modulation. / Graduation date: 2006
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28964 |
| Date | 14 June 2005 |
| Creators | Munsee, Craig L. |
| Contributors | Wager, John F. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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