Ultraviolet Multiphoton Photoemission Voltage Contrast Measurement System
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2005-Feb-15
This article describes a photoemission voltage contrast measurement system which utilizes two photon photoemission with a picosecond laser source of energy just below the work function of the material on a circuit under test. Photoemission induced by single ultraviolet (UV) photons results in a very small kinetic energy of the emitted photoelectrons as they leave the sample under test. Their kinetic energy is simply the excess energy of the photon energy compared to the work function of the material. Most technology relevant materials have work function around 4.5 eV (particularly with the contamination present on these surfaces).