Au Devices Research Articles

The slow-mode surface plasmon in planar metal-oxide-metal tunnel junctions

We present calculations of the properties of the slow-mode surface plasmon supported by certain planar metal-oxide-metal tunnel junctions. We study the Al–Al oxide–Ag and Al–Al oxide–Au device structures commonly used in light-emission experiments and give the dispersion, propagation decay length, and field profile of the mode in devices of typical dimensions over the energy range 1.4–3.8 eV. We also consider the dependence of the dispersion and decay length on the thickness of the oxide barrier and the likely effect of interface roughness. The bearing of these results on roughness-coupled interconversion between the slow- and fast-mode plasmons is discussed, and we comment on the possibilty of obtaining radiation directly from the slow mode.

Migration of gold atoms through thin silicon oxide films

Rapid migration of the gold electrode on C–SiOx–Au devices has been found for temperatures above the Au/Si eutectic point. Approximate concentration profiles have been determined by means of Rutherford scattering. Electrical measurements have been performed on both virgin and diffused devices. Comment is made on the relevance of electrode migration to the forming process and bistable memory switching in metal-insulator-metal devices.

Pulse experiments on electroformed mim structures

Voltage pulses of amplitude from 0 to 10 V, width 1 μs to 10 ms and with a wide range of repetition frequencies have been applied to electroformed Al-SiO x -Au devices and the pulsed current-voltage characteristics have been examined. The peak currents observed were up to 28 times larger than those obtained under d.c. bias conditions. It is argued that these results can be understood in terms of the filamentary model of conduction in electroformed devices but are in quantitative disagreement with the theory in its present form. Attempts to estimate the energy required for switching a device into a high impedance state were made using single 1 μs voltage pulses. These are compared with similar experiments reported in the literature. It is suggested that the present experiments yield the only unequivocal upper limit for the energy required to switch a device into a high impedance state.

TUNNELING INTO INTERFACE STATES OF MOS STRUCTURES

Measurements of the dc conductance of Si-SiO2–(Cr+Au) devices using P++-type Si and thin oxide layers (<50 Å) show one to two orders of magnitude increase of dc conductance of tunneling into the forbidden semiconductor band by changing from dry oxygen grown to steam grown and to annealed steam-grown oxide layers. The effect is explained by a corresponding increase of interface state density well known for thicker oxide layers (≈ 1000 Å).