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High Current Pulsed E-Beam Source

IP.com Disclosure Number: IPCOM000039478D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chiu, GLT: AUTHOR [+2]

Abstract

Electron beams are used for testing devices and have many advantages. No other technique can match the spatial resolution and depth of field obtainable with electron optics. Also, the collection of the secondary electrons emitted from the device under test is much easier than with other techniques. An electron source with greatly enhanced speed and electron current over existing guns (thermionic or field emission) is described that is useful for high-speed non-contact testing of devices. The key features of this gun are the use of ultrafast laser pulses to generate short electron pulses via photoemission or photon-assisted tunneling. These pulses can have photon energies above the work function of most simple metals.

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High Current Pulsed E-Beam Source

Electron beams are used for testing devices and have many advantages. No other technique can match the spatial resolution and depth of field obtainable with electron optics. Also, the collection of the secondary electrons emitted from the device under test is much easier than with other techniques. An electron source with greatly enhanced speed and electron current over existing guns (thermionic or field emission) is described that is useful for high-speed non- contact testing of devices. The key features of this gun are the use of ultrafast laser pulses to generate short electron pulses via photoemission or photon- assisted tunneling. These pulses can have photon energies above the work function of most simple metals. A CW mode-locked Nd-YAG laser is used which generates 80 psec optical pulses at a repetition rate between 80 and 100 MHz and with over 10 watts of average power at the fundamental wavelength of 1.06 micrometers. The pulses from this laser are compressed in a fiber-grating pair optical compressor and subsequently frequency doubled in a 5 mm KTP crystal to yield 2 ps pulses at 532 nm and an average power in excess of 1 W. This short optical pulse is frequency doubled in a KD*P crystal to generate photons at 266 nm (4.66 eV), above the work function of silver, copper, aluminum or tungsten, for example. A very conservative estimate of 1% doubling efficiency (10 mw average power) yields in excess of 108 photons in a 1.5 psec pulse and a repetition rate of 80 MHz. By focusing this light on a thin met...