Browsing by Author "Rost, Timothy Alan"

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    A thin film lithium niobate ferroelectric transistor
    (1991) Rost, Timothy Alan; Rabson, Thomas A.
    The incorporation of a thin film of LiNbO$\sb3$ in a conventional MOS (metal-oxide-semiconductor) structure gives the possibility of two fundamentally different types of computer memory architectures. One, based on ferroelectric switching, involves the reorganization of charge in the transistor channel to compensate for the change in surface polarization. Another, based on the bulk photovoltaic effect, creates a change in the threshold of the transistor when exposed to incident light. With the use of a molybdenum liftoff process, such ferroelectric transistors have been realized. The properties of these transistors have been measured before and after exposure to laser illumination, and before and after the application of voltage pulses.
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    Polarization reversal in thin film lithium niobate on silicon
    (1990) Rost, Timothy Alan; Rabson, Thomas A.
    The spontaneous polarization of thin film LiNbO$\sb3$ has been shown to be reversible with the application of an electric field at room temperature. This electric field is applied across the sample in the form of a voltage pulse, and polarization reversal is detected either as a photocurrent reversal, or as a current transient whose integrated area is proportional to the spontaneous polarization. For 80 mil$\sp2$ size areas of thickness.3 $\mu$m, the fastest switching speed was 500 ns. The samples consisted of a silicon substrate, a thin film of LiNbO$\sb3$ and a metal contact to form an MFS (metalferroelectric-semiconductor) structure. The LiNbO$\sb3$ film was formed by rf sputtering LiNbO$\sb3$ onto heated $\langle111\rangle$ silicon substrates.