A field-effect transistor in which the ferroelectric lithium niobate (LiNbO3) replaces the oxide in a conventional metal-oxide-semiconductor transistor has been fabricated. The channel conductance of this device has been shown to be strongly affected by the application of voltage pulses between the gate of the device and the substrate. A reduction of channel current of nearly 140 μA was observed after the application of a voltage pulse of −30 V and partially restored with a+10-V pulse. This behavior was found to be consistent with the influence of the polarization charge of the LiNbO3 layer on the carriers in the channel. This is the first observation of such behavior in a metal-ferroelectric-semiconductor field-effect transistor without the growth of a buffer layer between the semiconductor and ferroelectric to prevent charge injection.

The deposition of thin films of lithium niobate (LiNbO3) on silicon with rf magnetron sputtering has been investigated. A matrix of experiments was designed to determine the effect of several parameters on the resulting film quality. Under optimized conditions, oriented polycrystalline films of LiNbO3 are produced that exhibit a columnar grain structure with the polar axis normal to the substrate surface. Deviations from sputtering parameters optimized for producing LiNbO3, have been shown to produce films of varying proportions of either LiNb3O8 or Li3NbO4 with LiNbO3. The stoichiometry, microstructure, and electrical properties of selected films have been investigated with Rutherford backscattering, diffractometry, transmission electron microscopy, and a variety of electrical measurement techniques.

Epitaxial growth of lithium niobate thin films from a singlesource organometallic precursor using metalorganic chemical vapor deposition

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Thin films of LiNbO have been RF sputter deposited on silicon and sapphire substrates. A number of analytical techniques have been used to determine the physical structure of these films. This analysis shows that the resulting films are stoichiometric LiNbO(3) and oriented polycrystalline in nature. It is now possible to consider applications which utilize the unique properties of these films.