Characterizing voltage contrast in photoelectron emission microscopy.

A non-destructive technique for obtaining voltage contrast information with photoelectron emission microscopy is described. Samples consisting of electrically isolated metal lines were used to quantify voltage contrast in photoelectron emission microscopy. The voltage contrast behaviour is characterized by comparing measured voltage contrast with calculated voltage contrast from two electrostatic models. Measured voltage contrast was found to agree closely with the calculated voltage contrast, demonstrating that voltage contrast in photoelectron emission microscopy can be used to probe local voltage information in microelectronic devices in a non-intrusive fashion.

Spontaneous ordering of oxide nanostructures

We report the spontaneous formation of uniformly distributed arrays of "tips" (tall conical hillocks) upon oxidation of palladium (Pd) thin films. The formation of the palladium oxide tips depended on the thickness and granularity of the Pd film and on annealing and oxidation conditions. As the Pd film thickness increased from 40 to 200 nanometers, the average height of the tips increased from 0.5 to 1.2 micrometers, their height distribution became broader, and their density decreased from 55 x 10(6) to 12 x 10(6) per square centimeter. Enhanced photoelectron emission from locations corresponding to the tips suggests their possible use in field emission applications.